diff --git a/dll/win32/windowscodecs/bitmap.c b/dll/win32/windowscodecs/bitmap.c
index a44f5bd7b39..7959da6911d 100644
--- a/dll/win32/windowscodecs/bitmap.c
+++ b/dll/win32/windowscodecs/bitmap.c
@@ -1,5 +1,6 @@
 /*
  * Copyright 2012 Vincent Povirk for CodeWeavers
+ * Copyright 2016 Dmitry Timoshkov
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -16,7 +17,9 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  */
 
+#ifndef __REACTOS__
 #include "config.h"
+#endif
 
 #include <stdarg.h>
 
@@ -28,6 +31,7 @@
 
 #include "wincodecs_private.h"
 
+#include "wine/asm.h"
 #include "wine/debug.h"
 
 WINE_DEFAULT_DEBUG_CHANNEL(wincodecs);
@@ -38,7 +42,7 @@ WINE_DEFAULT_DEBUG_CHANNEL(wincodecs);
 typedef struct BitmapImpl {
     IMILUnknown1 IMILUnknown1_iface;
     LONG ref;
-    IMILBitmapSource IMILBitmapSource_iface;
+    IMILBitmap IMILBitmap_iface;
     IWICBitmap IWICBitmap_iface;
     IMILUnknown2 IMILUnknown2_iface;
     IWICPalette *palette;
@@ -68,9 +72,9 @@ static inline BitmapImpl *impl_from_IWICBitmap(IWICBitmap *iface)
     return CONTAINING_RECORD(iface, BitmapImpl, IWICBitmap_iface);
 }
 
-static inline BitmapImpl *impl_from_IMILBitmapSource(IMILBitmapSource *iface)
+static inline BitmapImpl *impl_from_IMILBitmap(IMILBitmap *iface)
 {
-    return CONTAINING_RECORD(iface, BitmapImpl, IMILBitmapSource_iface);
+    return CONTAINING_RECORD(iface, BitmapImpl, IMILBitmap_iface);
 }
 
 static inline BitmapImpl *impl_from_IMILUnknown1(IMILUnknown1 *iface)
@@ -254,7 +258,7 @@ static HRESULT WINAPI BitmapImpl_QueryInterface(IWICBitmap *iface, REFIID iid,
     else if (IsEqualIID(&IID_IMILBitmap, iid) ||
              IsEqualIID(&IID_IMILBitmapSource, iid))
     {
-        *ppv = &This->IMILBitmapSource_iface;
+        *ppv = &This->IMILBitmap_iface;
     }
     else
     {
@@ -478,51 +482,30 @@ static const IWICBitmapVtbl BitmapImpl_Vtbl = {
     BitmapImpl_SetResolution
 };
 
-static HRESULT WINAPI IMILBitmapImpl_QueryInterface(IMILBitmapSource *iface, REFIID iid,
+static HRESULT WINAPI IMILBitmapImpl_QueryInterface(IMILBitmap *iface, REFIID iid,
     void **ppv)
 {
-    BitmapImpl *This = impl_from_IMILBitmapSource(iface);
+    BitmapImpl *This = impl_from_IMILBitmap(iface);
     TRACE("(%p,%s,%p)\n", iface, debugstr_guid(iid), ppv);
-
-    if (!ppv) return E_INVALIDARG;
-
-    if (IsEqualIID(&IID_IUnknown, iid) ||
-        IsEqualIID(&IID_IMILBitmap, iid) ||
-        IsEqualIID(&IID_IMILBitmapSource, iid))
-    {
-        IUnknown_AddRef(&This->IMILBitmapSource_iface);
-        *ppv = &This->IMILBitmapSource_iface;
-        return S_OK;
-    }
-    else if (IsEqualIID(&IID_IWICBitmap, iid) ||
-             IsEqualIID(&IID_IWICBitmapSource, iid))
-    {
-        IUnknown_AddRef(&This->IWICBitmap_iface);
-        *ppv = &This->IWICBitmap_iface;
-        return S_OK;
-    }
-
-    FIXME("unknown interface %s\n", debugstr_guid(iid));
-    *ppv = NULL;
-    return E_NOINTERFACE;
+    return IWICBitmap_QueryInterface(&This->IWICBitmap_iface, iid, ppv);
 }
 
-static ULONG WINAPI IMILBitmapImpl_AddRef(IMILBitmapSource *iface)
+static ULONG WINAPI IMILBitmapImpl_AddRef(IMILBitmap *iface)
 {
-    BitmapImpl *This = impl_from_IMILBitmapSource(iface);
+    BitmapImpl *This = impl_from_IMILBitmap(iface);
     return IWICBitmap_AddRef(&This->IWICBitmap_iface);
 }
 
-static ULONG WINAPI IMILBitmapImpl_Release(IMILBitmapSource *iface)
+static ULONG WINAPI IMILBitmapImpl_Release(IMILBitmap *iface)
 {
-    BitmapImpl *This = impl_from_IMILBitmapSource(iface);
+    BitmapImpl *This = impl_from_IMILBitmap(iface);
     return IWICBitmap_Release(&This->IWICBitmap_iface);
 }
 
-static HRESULT WINAPI IMILBitmapImpl_GetSize(IMILBitmapSource *iface,
+static HRESULT WINAPI IMILBitmapImpl_GetSize(IMILBitmap *iface,
     UINT *width, UINT *height)
 {
-    BitmapImpl *This = impl_from_IMILBitmapSource(iface);
+    BitmapImpl *This = impl_from_IMILBitmap(iface);
     TRACE("(%p,%p,%p)\n", iface, width, height);
     return IWICBitmap_GetSize(&This->IWICBitmap_iface, width, height);
 }
@@ -556,10 +539,10 @@ static const struct
     { &GUID_WICPixelFormat32bppCMYK, 0x1c }
 };
 
-static HRESULT WINAPI IMILBitmapImpl_GetPixelFormat(IMILBitmapSource *iface,
+static HRESULT WINAPI IMILBitmapImpl_GetPixelFormat(IMILBitmap *iface,
     int *format)
 {
-    BitmapImpl *This = impl_from_IMILBitmapSource(iface);
+    BitmapImpl *This = impl_from_IMILBitmap(iface);
     int i;
 
     TRACE("(%p,%p)\n", iface, format);
@@ -581,33 +564,33 @@ static HRESULT WINAPI IMILBitmapImpl_GetPixelFormat(IMILBitmapSource *iface,
     return S_OK;
 }
 
-static HRESULT WINAPI IMILBitmapImpl_GetResolution(IMILBitmapSource *iface,
+static HRESULT WINAPI IMILBitmapImpl_GetResolution(IMILBitmap *iface,
     double *dpix, double *dpiy)
 {
-    BitmapImpl *This = impl_from_IMILBitmapSource(iface);
+    BitmapImpl *This = impl_from_IMILBitmap(iface);
     TRACE("(%p,%p,%p)\n", iface, dpix, dpiy);
     return IWICBitmap_GetResolution(&This->IWICBitmap_iface, dpix, dpiy);
 }
 
-static HRESULT WINAPI IMILBitmapImpl_CopyPalette(IMILBitmapSource *iface,
+static HRESULT WINAPI IMILBitmapImpl_CopyPalette(IMILBitmap *iface,
     IWICPalette *palette)
 {
-    BitmapImpl *This = impl_from_IMILBitmapSource(iface);
+    BitmapImpl *This = impl_from_IMILBitmap(iface);
     TRACE("(%p,%p)\n", iface, palette);
     return IWICBitmap_CopyPalette(&This->IWICBitmap_iface, palette);
 }
 
-static HRESULT WINAPI IMILBitmapImpl_CopyPixels(IMILBitmapSource *iface,
+static HRESULT WINAPI IMILBitmapImpl_CopyPixels(IMILBitmap *iface,
     const WICRect *rc, UINT stride, UINT size, BYTE *buffer)
 {
-    BitmapImpl *This = impl_from_IMILBitmapSource(iface);
+    BitmapImpl *This = impl_from_IMILBitmap(iface);
     TRACE("(%p,%p,%u,%u,%p)\n", iface, rc, stride, size, buffer);
     return IWICBitmap_CopyPixels(&This->IWICBitmap_iface, rc, stride, size, buffer);
 }
 
-static HRESULT WINAPI IMILBitmapImpl_unknown1(IMILBitmapSource *iface, void **ppv)
+static HRESULT WINAPI IMILBitmapImpl_unknown1(IMILBitmap *iface, void **ppv)
 {
-    BitmapImpl *This = impl_from_IMILBitmapSource(iface);
+    BitmapImpl *This = impl_from_IMILBitmap(iface);
 
     TRACE("(%p,%p)\n", iface, ppv);
 
@@ -619,41 +602,41 @@ static HRESULT WINAPI IMILBitmapImpl_unknown1(IMILBitmapSource *iface, void **pp
     return S_OK;
 }
 
-static HRESULT WINAPI IMILBitmapImpl_Lock(IMILBitmapSource *iface, const WICRect *rc, DWORD flags, IWICBitmapLock **lock)
+static HRESULT WINAPI IMILBitmapImpl_Lock(IMILBitmap *iface, const WICRect *rc, DWORD flags, IWICBitmapLock **lock)
 {
-    BitmapImpl *This = impl_from_IMILBitmapSource(iface);
+    BitmapImpl *This = impl_from_IMILBitmap(iface);
     TRACE("(%p,%p,%08x,%p)\n", iface, rc, flags, lock);
     return IWICBitmap_Lock(&This->IWICBitmap_iface, rc, flags, lock);
 }
 
-static HRESULT WINAPI IMILBitmapImpl_Unlock(IMILBitmapSource *iface, IWICBitmapLock *lock)
+static HRESULT WINAPI IMILBitmapImpl_Unlock(IMILBitmap *iface, IWICBitmapLock *lock)
 {
     TRACE("(%p,%p)\n", iface, lock);
     IWICBitmapLock_Release(lock);
     return S_OK;
 }
 
-static HRESULT WINAPI IMILBitmapImpl_SetPalette(IMILBitmapSource *iface, IWICPalette *palette)
+static HRESULT WINAPI IMILBitmapImpl_SetPalette(IMILBitmap *iface, IWICPalette *palette)
 {
-    BitmapImpl *This = impl_from_IMILBitmapSource(iface);
+    BitmapImpl *This = impl_from_IMILBitmap(iface);
     TRACE("(%p,%p)\n", iface, palette);
     return IWICBitmap_SetPalette(&This->IWICBitmap_iface, palette);
 }
 
-static HRESULT WINAPI IMILBitmapImpl_SetResolution(IMILBitmapSource *iface, double dpix, double dpiy)
+static HRESULT WINAPI IMILBitmapImpl_SetResolution(IMILBitmap *iface, double dpix, double dpiy)
 {
-    BitmapImpl *This = impl_from_IMILBitmapSource(iface);
+    BitmapImpl *This = impl_from_IMILBitmap(iface);
     TRACE("(%p,%f,%f)\n", iface, dpix, dpiy);
     return IWICBitmap_SetResolution(&This->IWICBitmap_iface, dpix, dpiy);
 }
 
-static HRESULT WINAPI IMILBitmapImpl_AddDirtyRect(IMILBitmapSource *iface, const WICRect *rc)
+static HRESULT WINAPI IMILBitmapImpl_AddDirtyRect(IMILBitmap *iface, const WICRect *rc)
 {
     FIXME("(%p,%p): stub\n", iface, rc);
     return E_NOTIMPL;
 }
 
-static const IMILBitmapSourceVtbl IMILBitmapImpl_Vtbl =
+static const IMILBitmapVtbl IMILBitmapImpl_Vtbl =
 {
     IMILBitmapImpl_QueryInterface,
     IMILBitmapImpl_AddRef,
@@ -674,6 +657,7 @@ static const IMILBitmapSourceVtbl IMILBitmapImpl_Vtbl =
 static HRESULT WINAPI IMILUnknown1Impl_QueryInterface(IMILUnknown1 *iface, REFIID iid,
     void **ppv)
 {
+    /* It's not clear what interface should be returned here */
     FIXME("(%p,%s,%p): stub\n", iface, debugstr_guid(iid), ppv);
     *ppv = NULL;
     return E_NOINTERFACE;
@@ -835,7 +819,7 @@ HRESULT BitmapImpl_Create(UINT uiWidth, UINT uiHeight, UINT stride, UINT datasiz
     }
 
     This->IWICBitmap_iface.lpVtbl = &BitmapImpl_Vtbl;
-    This->IMILBitmapSource_iface.lpVtbl = &IMILBitmapImpl_Vtbl;
+    This->IMILBitmap_iface.lpVtbl = &IMILBitmapImpl_Vtbl;
     This->IMILUnknown1_iface.lpVtbl = &IMILUnknown1Impl_Vtbl;
     This->IMILUnknown2_iface.lpVtbl = &IMILUnknown2Impl_Vtbl;
     This->ref = 1;
diff --git a/dll/win32/windowscodecs/converter.c b/dll/win32/windowscodecs/converter.c
index c3476c3efa4..dcc2f05693f 100644
--- a/dll/win32/windowscodecs/converter.c
+++ b/dll/win32/windowscodecs/converter.c
@@ -85,14 +85,6 @@ typedef struct FormatConverter {
 } FormatConverter;
 
 /* https://www.w3.org/Graphics/Color/srgb */
-#ifndef __REACTOS__
-static inline float from_sRGB_component(float f)
-{
-    if (f <= 0.04045f) return f / 12.92f;
-    return powf((f + 0.055f) / 1.055f, 2.4f);
-}
-#endif
-
 static inline float to_sRGB_component(float f)
 {
     if (f <= 0.0031308f) return 12.92f * f;
@@ -100,6 +92,12 @@ static inline float to_sRGB_component(float f)
 }
 
 #if 0 /* FIXME: enable once needed */
+static inline float from_sRGB_component(float f)
+{
+    if (f <= 0.04045f) return f / 12.92f;
+    return powf((f + 0.055f) / 1.055f, 2.4f);
+}
+
 static void from_sRGB(BYTE *bgr)
 {
     float r, g, b;
@@ -460,8 +458,9 @@ static HRESULT copypixels_to_32bppBGRA(struct FormatConverter *This, const WICRe
                     dstpixel=(DWORD*)dstrow;
                     for (x=0; x<prc->Width; x++)
                     {
+                        srcbyte++;
                         *dstpixel++ = 0xff000000|(*srcbyte<<16)|(*srcbyte<<8)|*srcbyte;
-                        srcbyte+=2;
+                        srcbyte++;
                     }
                     srcrow += srcstride;
                     dstrow += cbStride;
@@ -778,9 +777,9 @@ static HRESULT copypixels_to_32bppBGRA(struct FormatConverter *This, const WICRe
                     dstpixel=(DWORD*)dstrow;
                     for (x=0; x<prc->Width; x++) {
                         BYTE red, green, blue;
-                        red = *srcpixel++; srcpixel++;
-                        green = *srcpixel++; srcpixel++;
-                        blue = *srcpixel++; srcpixel++;
+                        srcpixel++; red = *srcpixel++;
+                        srcpixel++; green = *srcpixel++;
+                        srcpixel++; blue = *srcpixel++;
                         *dstpixel++=0xff000000|red<<16|green<<8|blue;
                     }
                     srcrow += srcstride;
@@ -822,10 +821,10 @@ static HRESULT copypixels_to_32bppBGRA(struct FormatConverter *This, const WICRe
                     dstpixel=(DWORD*)dstrow;
                     for (x=0; x<prc->Width; x++) {
                         BYTE red, green, blue, alpha;
-                        red = *srcpixel++; srcpixel++;
-                        green = *srcpixel++; srcpixel++;
-                        blue = *srcpixel++; srcpixel++;
-                        alpha = *srcpixel++; srcpixel++;
+                        srcpixel++; red = *srcpixel++;
+                        srcpixel++; green = *srcpixel++;
+                        srcpixel++; blue = *srcpixel++;
+                        srcpixel++; alpha = *srcpixel++;
                         *dstpixel++=alpha<<24|red<<16|green<<8|blue;
                     }
                     srcrow += srcstride;
@@ -872,11 +871,47 @@ static HRESULT copypixels_to_32bppRGBA(struct FormatConverter *This, const WICRe
     switch (source_format)
     {
     case format_32bppRGB:
+        if (prc)
+        {
+            INT x, y;
+
+            hr = IWICBitmapSource_CopyPixels(This->source, prc, cbStride, cbBufferSize, pbBuffer);
+            if (FAILED(hr)) return hr;
+
+            /* set all alpha values to 255 */
+            for (y=0; y<prc->Height; y++)
+                for (x=0; x<prc->Width; x++)
+                    pbBuffer[cbStride*y+4*x+3] = 0xff;
+        }
+        return S_OK;
+
     case format_32bppRGBA:
-    case format_32bppPRGBA:
         if (prc)
             return IWICBitmapSource_CopyPixels(This->source, prc, cbStride, cbBufferSize, pbBuffer);
         return S_OK;
+
+    case format_32bppPRGBA:
+        if (prc)
+        {
+            INT x, y;
+
+            hr = IWICBitmapSource_CopyPixels(This->source, prc, cbStride, cbBufferSize, pbBuffer);
+            if (FAILED(hr)) return hr;
+
+            for (y=0; y<prc->Height; y++)
+                for (x=0; x<prc->Width; x++)
+                {
+                    BYTE alpha = pbBuffer[cbStride*y+4*x+3];
+                    if (alpha != 0 && alpha != 255)
+                    {
+                        pbBuffer[cbStride*y+4*x] = pbBuffer[cbStride*y+4*x] * 255 / alpha;
+                        pbBuffer[cbStride*y+4*x+1] = pbBuffer[cbStride*y+4*x+1] * 255 / alpha;
+                        pbBuffer[cbStride*y+4*x+2] = pbBuffer[cbStride*y+4*x+2] * 255 / alpha;
+                    }
+                }
+        }
+        return S_OK;
+
     default:
         hr = copypixels_to_32bppBGRA(This, prc, cbStride, cbBufferSize, pbBuffer, source_format);
         if (SUCCEEDED(hr) && prc)
@@ -1304,6 +1339,9 @@ static HRESULT copypixels_to_8bppGray(struct FormatConverter *This, const WICRec
         return hr;
     }
 
+    if (!prc)
+        return copypixels_to_24bppBGR(This, NULL, cbStride, cbBufferSize, pbBuffer, source_format);
+
     srcstride = 3 * prc->Width;
     srcdatasize = srcstride * prc->Height;
 
@@ -1311,7 +1349,7 @@ static HRESULT copypixels_to_8bppGray(struct FormatConverter *This, const WICRec
     if (!srcdata) return E_OUTOFMEMORY;
 
     hr = copypixels_to_24bppBGR(This, prc, srcstride, srcdatasize, srcdata, source_format);
-    if (SUCCEEDED(hr) && prc)
+    if (SUCCEEDED(hr))
     {
         INT x, y;
         BYTE *src = srcdata, *dst = pbBuffer;
@@ -1337,7 +1375,7 @@ static HRESULT copypixels_to_8bppGray(struct FormatConverter *This, const WICRec
     return hr;
 }
 
-static UINT rgb_to_palette_index(BYTE r, BYTE g, BYTE b, WICColor *colors, UINT count)
+static UINT rgb_to_palette_index(BYTE bgr[3], WICColor *colors, UINT count)
 {
     UINT best_diff, best_index, i;
 
@@ -1347,15 +1385,15 @@ static UINT rgb_to_palette_index(BYTE r, BYTE g, BYTE b, WICColor *colors, UINT
     for (i = 0; i < count; i++)
     {
         BYTE pal_r, pal_g, pal_b;
-        DWORD diff_r, diff_g, diff_b, diff;
+        UINT diff_r, diff_g, diff_b, diff;
 
         pal_r = colors[i] >> 16;
         pal_g = colors[i] >> 8;
         pal_b = colors[i];
 
-        diff_r = r - pal_r;
-        diff_g = g - pal_g;
-        diff_b = b - pal_b;
+        diff_r = bgr[2] - pal_r;
+        diff_g = bgr[1] - pal_g;
+        diff_b = bgr[0] - pal_b;
 
         diff = diff_r * diff_r + diff_g * diff_g + diff_b * diff_b;
         if (diff == 0) return i;
@@ -1386,6 +1424,9 @@ static HRESULT copypixels_to_8bppIndexed(struct FormatConverter *This, const WIC
         return S_OK;
     }
 
+    if (!prc)
+        return copypixels_to_24bppBGR(This, NULL, cbStride, cbBufferSize, pbBuffer, source_format);
+
     if (!This->palette) return WINCODEC_ERR_WRONGSTATE;
 
     hr = IWICPalette_GetColors(This->palette, 256, colors, &count);
@@ -1398,7 +1439,7 @@ static HRESULT copypixels_to_8bppIndexed(struct FormatConverter *This, const WIC
     if (!srcdata) return E_OUTOFMEMORY;
 
     hr = copypixels_to_24bppBGR(This, prc, srcstride, srcdatasize, srcdata, source_format);
-    if (SUCCEEDED(hr) && prc)
+    if (SUCCEEDED(hr))
     {
         INT x, y;
         BYTE *src = srcdata, *dst = pbBuffer;
@@ -1409,7 +1450,7 @@ static HRESULT copypixels_to_8bppIndexed(struct FormatConverter *This, const WIC
 
             for (x = 0; x < prc->Width; x++)
             {
-                dst[x] = rgb_to_palette_index(bgr[2], bgr[1], bgr[0], colors, count);
+                dst[x] = rgb_to_palette_index(bgr, colors, count);
                 bgr += 3;
             }
             src += srcstride;
diff --git a/dll/win32/windowscodecs/icnsformat.c b/dll/win32/windowscodecs/icnsformat.c
index 02e8ee97e6d..8194bc508a5 100644
--- a/dll/win32/windowscodecs/icnsformat.c
+++ b/dll/win32/windowscodecs/icnsformat.c
@@ -75,7 +75,6 @@
 #undef SetRect
 #undef ShowCursor
 #undef UnionRect
-#undef DPRINTF
 #endif
 
 #define COBJMACROS
diff --git a/dll/win32/windowscodecs/metadataquery.c b/dll/win32/windowscodecs/metadataquery.c
index c4c188d8c9d..79340427547 100644
--- a/dll/win32/windowscodecs/metadataquery.c
+++ b/dll/win32/windowscodecs/metadataquery.c
@@ -242,7 +242,6 @@ static HRESULT get_token(struct string_t *elem, PROPVARIANT *id, PROPVARIANT *sc
         bstr = next_token.u.bstrVal;
 
         end++;
-        p = end;
         while (*end && *end != '}' && end - start < elem->len)
         {
             if (*end == '\\') end++;
@@ -925,7 +924,7 @@ HRESULT WINAPI WICMapSchemaToName(REFGUID format, LPWSTR schema, UINT len, WCHAR
                     return HRESULT_FROM_WIN32(ERROR_INSUFFICIENT_BUFFER);
             }
 
-            if (ret_len) *ret_len = lstrlenW(name2schema[i].name) + 1;
+            *ret_len = lstrlenW(name2schema[i].name) + 1;
             return S_OK;
         }
     }
diff --git a/dll/win32/windowscodecs/msvc.h b/dll/win32/windowscodecs/msvc.h
index a694b8601bb..6bb78f43af6 100644
--- a/dll/win32/windowscodecs/msvc.h
+++ b/dll/win32/windowscodecs/msvc.h
@@ -1,6 +1,4 @@
 
-#define __ASM_STDCALL_FUNC(name,args,code)
-
 #define typeof(X_) __typeof_ ## X_
 
 struct IMILUnknown1;
diff --git a/dll/win32/windowscodecs/palette.c b/dll/win32/windowscodecs/palette.c
index 1c1e85834b8..f99cbe00fd1 100644
--- a/dll/win32/windowscodecs/palette.c
+++ b/dll/win32/windowscodecs/palette.c
@@ -669,8 +669,8 @@ static HRESULT WINAPI PaletteImpl_InitializeFromBitmap(IWICPalette *palette,
     hr = IWICBitmapSource_GetPixelFormat(source, &format);
     if (hr != S_OK) return hr;
 
-    /* For interoperability with gdiplus where PixelFormat24bppRGB actully stored
-     * as BGR (and there is no a corresponding RGB format) we have to use 24bppBGR
+    /* For interoperability with gdiplus where PixelFormat24bppRGB is actually stored
+     * as BGR (and there is no corresponding RGB format), we have to use 24bppBGR
      * to avoid format conversions.
      */
     if (!IsEqualGUID(&format, &GUID_WICPixelFormat24bppBGR))
diff --git a/dll/win32/windowscodecs/pngformat.c b/dll/win32/windowscodecs/pngformat.c
index 7050c95121b..c0e272e86f0 100644
--- a/dll/win32/windowscodecs/pngformat.c
+++ b/dll/win32/windowscodecs/pngformat.c
@@ -332,6 +332,7 @@ MAKE_FUNCPTR(png_set_strip_16);
 MAKE_FUNCPTR(png_set_tRNS);
 MAKE_FUNCPTR(png_set_tRNS_to_alpha);
 MAKE_FUNCPTR(png_set_write_fn);
+MAKE_FUNCPTR(png_set_swap);
 MAKE_FUNCPTR(png_read_end);
 MAKE_FUNCPTR(png_read_image);
 MAKE_FUNCPTR(png_read_info);
@@ -398,6 +399,7 @@ static void *load_libpng(void)
         LOAD_FUNCPTR(png_set_tRNS);
         LOAD_FUNCPTR(png_set_tRNS_to_alpha);
         LOAD_FUNCPTR(png_set_write_fn);
+        LOAD_FUNCPTR(png_set_swap);
         LOAD_FUNCPTR(png_read_end);
         LOAD_FUNCPTR(png_read_image);
         LOAD_FUNCPTR(png_read_info);
@@ -620,7 +622,6 @@ static HRESULT WINAPI PngDecoder_Initialize(IWICBitmapDecoder *iface, IStream *p
     if (setjmp(jmpbuf))
     {
         ppng_destroy_read_struct(&This->png_ptr, &This->info_ptr, &This->end_info);
-        HeapFree(GetProcessHeap(), 0, row_pointers);
         This->png_ptr = NULL;
         hr = WINCODEC_ERR_UNKNOWNIMAGEFORMAT;
         goto end;
@@ -643,6 +644,10 @@ static HRESULT WINAPI PngDecoder_Initialize(IWICBitmapDecoder *iface, IStream *p
     color_type = ppng_get_color_type(This->png_ptr, This->info_ptr);
     bit_depth = ppng_get_bit_depth(This->png_ptr, This->info_ptr);
 
+    /* PNGs with bit-depth greater than 8 are network byte order. Windows does not expect this. */
+    if (bit_depth > 8)
+        ppng_set_swap(This->png_ptr);
+
     /* check for color-keyed alpha */
     transparency = ppng_get_tRNS(This->png_ptr, This->info_ptr, &trans, &num_trans, &trans_values);
 
@@ -816,6 +821,8 @@ static HRESULT WINAPI PngDecoder_Initialize(IWICBitmapDecoder *iface, IStream *p
 end:
     LeaveCriticalSection(&This->lock);
 
+    HeapFree(GetProcessHeap(), 0, row_pointers);
+
     return hr;
 }
 
@@ -1642,6 +1649,10 @@ static HRESULT WINAPI PngFrameEncode_WritePixels(IWICBitmapFrameEncode *iface,
             }
         }
 
+        /* Tell PNG we need to byte swap if writing a >8-bpp image */
+        if (This->format->bit_depth > 8)
+            ppng_set_swap(This->png_ptr);
+
         ppng_set_IHDR(This->png_ptr, This->info_ptr, This->width, This->height,
             This->format->bit_depth, This->format->color_type,
             This->interlace ? PNG_INTERLACE_ADAM7 : PNG_INTERLACE_NONE,
diff --git a/dll/win32/windowscodecs/precomp.h b/dll/win32/windowscodecs/precomp.h
index 144e085e442..0d0ac5c7af7 100644
--- a/dll/win32/windowscodecs/precomp.h
+++ b/dll/win32/windowscodecs/precomp.h
@@ -2,9 +2,6 @@
 #ifndef WINCODECS_PRECOMP_H
 #define WINCODECS_PRECOMP_H
 
-#include <wine/config.h>
-#include <wine/port.h>
-
 #include <stdarg.h>
 
 #define WIN32_NO_STATUS
diff --git a/dll/win32/windowscodecs/scaler.c b/dll/win32/windowscodecs/scaler.c
index d19e219feab..d6e56d096ea 100644
--- a/dll/win32/windowscodecs/scaler.c
+++ b/dll/win32/windowscodecs/scaler.c
@@ -1,5 +1,6 @@
 /*
  * Copyright 2010 Vincent Povirk for CodeWeavers
+ * Copyright 2016 Dmitry Timoshkov
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -224,7 +225,7 @@ static HRESULT WINAPI BitmapScaler_CopyPixels(IWICBitmapScaler *iface,
 
     if (!This->source)
     {
-        hr = WINCODEC_ERR_WRONGSTATE;
+        hr = WINCODEC_ERR_NOTINITIALIZED;
         goto end;
     }
 
@@ -395,30 +396,8 @@ static HRESULT WINAPI IMILBitmapScaler_QueryInterface(IMILBitmapScaler *iface, R
     void **ppv)
 {
     BitmapScaler *This = impl_from_IMILBitmapScaler(iface);
-
     TRACE("(%p,%s,%p)\n", iface, debugstr_guid(iid), ppv);
-
-    if (!ppv) return E_INVALIDARG;
-
-    if (IsEqualIID(&IID_IUnknown, iid) ||
-        IsEqualIID(&IID_IMILBitmapScaler, iid) ||
-        IsEqualIID(&IID_IMILBitmapSource, iid))
-    {
-        IUnknown_AddRef(&This->IMILBitmapScaler_iface);
-        *ppv = &This->IMILBitmapScaler_iface;
-        return S_OK;
-    }
-    else if (IsEqualIID(&IID_IWICBitmapScaler, iid) ||
-             IsEqualIID(&IID_IWICBitmapSource, iid))
-    {
-        IUnknown_AddRef(&This->IWICBitmapScaler_iface);
-        *ppv = &This->IWICBitmapScaler_iface;
-        return S_OK;
-    }
-
-    FIXME("unknown interface %s\n", debugstr_guid(iid));
-    *ppv = NULL;
-    return E_NOINTERFACE;
+    return IWICBitmapScaler_QueryInterface(&This->IWICBitmapScaler_iface, iid, ppv);
 }
 
 static ULONG WINAPI IMILBitmapScaler_AddRef(IMILBitmapScaler *iface)
@@ -437,12 +416,7 @@ static HRESULT WINAPI IMILBitmapScaler_GetSize(IMILBitmapScaler *iface,
     UINT *width, UINT *height)
 {
     BitmapScaler *This = impl_from_IMILBitmapScaler(iface);
-
     TRACE("(%p,%p,%p)\n", iface, width, height);
-
-    if (!This->source)
-        return WINCODEC_ERR_NOTINITIALIZED;
-
     return IWICBitmapScaler_GetSize(&This->IWICBitmapScaler_iface, width, height);
 }
 
@@ -473,12 +447,7 @@ static HRESULT WINAPI IMILBitmapScaler_GetResolution(IMILBitmapScaler *iface,
     double *dpix, double *dpiy)
 {
     BitmapScaler *This = impl_from_IMILBitmapScaler(iface);
-
     TRACE("(%p,%p,%p)\n", iface, dpix, dpiy);
-
-    if (!This->source)
-        return WINCODEC_ERR_NOTINITIALIZED;
-
     return IWICBitmapScaler_GetResolution(&This->IWICBitmapScaler_iface, dpix, dpiy);
 }
 
@@ -499,12 +468,7 @@ static HRESULT WINAPI IMILBitmapScaler_CopyPixels(IMILBitmapScaler *iface,
     const WICRect *rc, UINT stride, UINT size, BYTE *buffer)
 {
     BitmapScaler *This = impl_from_IMILBitmapScaler(iface);
-
     TRACE("(%p,%p,%u,%u,%p)\n", iface, rc, stride, size, buffer);
-
-    if (!This->source)
-        return WINCODEC_ERR_NOTINITIALIZED;
-
     return IWICBitmapScaler_CopyPixels(&This->IWICBitmapScaler_iface, rc, stride, size, buffer);
 }
 
diff --git a/dll/win32/windowscodecs/tiffformat.c b/dll/win32/windowscodecs/tiffformat.c
index d9b7c4c6096..6f4f6d06b74 100644
--- a/dll/win32/windowscodecs/tiffformat.c
+++ b/dll/win32/windowscodecs/tiffformat.c
@@ -289,6 +289,7 @@ static HRESULT tiff_get_decode_info(TIFF *tiff, tiff_decode_info *decode_info)
     decode_info->reverse_bgr = 0;
     decode_info->invert_grayscale = 0;
     decode_info->tiled = 0;
+    decode_info->source_bpp = 0;
 
     ret = pTIFFGetField(tiff, TIFFTAG_PHOTOMETRIC, &photometric);
     if (!ret)
diff --git a/dll/win32/windowscodecs/typeof.h b/dll/win32/windowscodecs/typeof.h
index b20434b7cce..91995864ac2 100644
--- a/dll/win32/windowscodecs/typeof.h
+++ b/dll/win32/windowscodecs/typeof.h
@@ -81,6 +81,7 @@ typedef void (__cdecl typeof(png_set_crc_action))(struct png_struct_def *, int,
 typedef void (__cdecl typeof(png_set_PLTE))(struct png_struct_def *, struct png_info_def *, const struct png_color_struct *, int);
 typedef void (__cdecl typeof(png_set_tRNS))(struct png_struct_def *, struct png_info_def *, const unsigned char *, int, const struct png_color_16_struct *);
 typedef void (__cdecl typeof(png_set_filter))(struct png_struct_def *, int, int);
+typedef void (__cdecl typeof(png_set_swap))(struct png_struct_def *);
 typedef void *thandle_t_1;
 typedef __typeof_intptr (*TIFFReadWriteProc_1)(thandle_t_1, void *, __typeof_intptr);
 typedef unsigned int (*TIFFSeekProc_1)(void *, unsigned int, int);
diff --git a/dll/win32/windowscodecs/wincodecs_private.h b/dll/win32/windowscodecs/wincodecs_private.h
index 22af9a12fbb..ff192c26399 100644
--- a/dll/win32/windowscodecs/wincodecs_private.h
+++ b/dll/win32/windowscodecs/wincodecs_private.h
@@ -53,7 +53,23 @@ DECLARE_INTERFACE_(IMILBitmapSource,IUnknown)
     STDMETHOD_(HRESULT,GetResolution)(THIS_ double *,double *) PURE;
     STDMETHOD_(HRESULT,CopyPalette)(THIS_ IWICPalette *) PURE;
     STDMETHOD_(HRESULT,CopyPixels)(THIS_ const WICRect *,UINT,UINT,BYTE *) PURE;
-    /*** IMILBitmapSource methods ***/
+};
+#undef INTERFACE
+
+#define INTERFACE IMILBitmap
+DECLARE_INTERFACE_(IMILBitmap,IMILBitmapSource)
+{
+    /*** IUnknown methods ***/
+    STDMETHOD_(HRESULT,QueryInterface)(THIS_ REFIID,void **) PURE;
+    STDMETHOD_(ULONG,AddRef)(THIS) PURE;
+    STDMETHOD_(ULONG,Release)(THIS) PURE;
+    /*** IWICBitmapSource methods ***/
+    STDMETHOD_(HRESULT,GetSize)(THIS_ UINT *,UINT *) PURE;
+    STDMETHOD_(HRESULT,GetPixelFormat)(THIS_ int *) PURE;
+    STDMETHOD_(HRESULT,GetResolution)(THIS_ double *,double *) PURE;
+    STDMETHOD_(HRESULT,CopyPalette)(THIS_ IWICPalette *) PURE;
+    STDMETHOD_(HRESULT,CopyPixels)(THIS_ const WICRect *,UINT,UINT,BYTE *) PURE;
+    /*** IMILBitmap methods ***/
     STDMETHOD_(HRESULT,unknown1)(THIS_ void **) PURE;
     STDMETHOD_(HRESULT,Lock)(THIS_ const WICRect *,DWORD,IWICBitmapLock **) PURE;
     STDMETHOD_(HRESULT,Unlock)(THIS_ IWICBitmapLock *) PURE;
@@ -64,7 +80,7 @@ DECLARE_INTERFACE_(IMILBitmapSource,IUnknown)
 #undef INTERFACE
 
 #define INTERFACE IMILBitmapScaler
-DECLARE_INTERFACE_(IMILBitmapScaler,IUnknown)
+DECLARE_INTERFACE_(IMILBitmapScaler,IMILBitmapSource)
 {
     /*** IUnknown methods ***/
     STDMETHOD_(HRESULT,QueryInterface)(THIS_ REFIID,void **) PURE;
@@ -78,26 +94,11 @@ DECLARE_INTERFACE_(IMILBitmapScaler,IUnknown)
     STDMETHOD_(HRESULT,CopyPixels)(THIS_ const WICRect *,UINT,UINT,BYTE *) PURE;
     /*** IMILBitmapScaler methods ***/
     STDMETHOD_(HRESULT,unknown1)(THIS_ void **) PURE;
-    STDMETHOD_(HRESULT,Initialize)(THIS_ IMILBitmapSource *,UINT,UINT,WICBitmapInterpolationMode);
+    STDMETHOD_(HRESULT,Initialize)(THIS_ IMILBitmapSource *,UINT,UINT,WICBitmapInterpolationMode) PURE;
 };
 #undef INTERFACE
 
-#ifdef __i386__  /* thiscall functions are i386-specific */
-
-#define THISCALL(func) __thiscall_ ## func
-#define DEFINE_THISCALL_WRAPPER(func,args) \
-    extern typeof(func) THISCALL(func); \
-    __ASM_STDCALL_FUNC(__thiscall_ ## func, args, \
-                    "popl %eax\n\t" \
-                    "pushl %ecx\n\t" \
-                    "pushl %eax\n\t" \
-                    "jmp " __ASM_NAME(#func) __ASM_STDCALL(args) )
-#else /* __i386__ */
-
-#define THISCALL(func) func
-#define DEFINE_THISCALL_WRAPPER(func,args) /* nothing */
-
-#endif /* __i386__ */
+#define THISCALLMETHOD_(type,method)  type (__thiscall *method)
 
 #define INTERFACE IMILUnknown1
 DECLARE_INTERFACE_(IMILUnknown1,IUnknown)
diff --git a/media/doc/README.WINE b/media/doc/README.WINE
index def03896c75..876663af0de 100644
--- a/media/doc/README.WINE
+++ b/media/doc/README.WINE
@@ -197,7 +197,7 @@ dll/win32/version             # Synced to WineStaging-4.18
 dll/win32/vssapi              # Synced to WineStaging-4.18
 dll/win32/wbemdisp            # Synced to WineStaging-4.18
 dll/win32/wbemprox            # Synced to WineStaging-4.18
-dll/win32/windowscodecs       # Synced to WineStaging-4.0
+dll/win32/windowscodecs       # Synced to WineStaging-4.18
 dll/win32/windowscodecsext    # Synced to WineStaging-2.9
 dll/win32/winemp3.acm         # Synced to WineStaging-3.3
 dll/win32/wing32              # Synced to WineStaging-3.3