This ports back the following commits about lossless PNG-shrinking:
0.4.15-dev-6410-g cf4bb8fced [WALLPAPERS] Optimize PNG images (#5506)
0.4.15-dev-6398-g e5993f13f0 [REACTOS] Optimize PNG images (#5492)
0.4.15-dev-6376-g 8f3a09722e [MSPAINT] Optimize images for help docs (#5486)
Most of those PNGs have not been touched ever since we switched from SVN to git, so they can safely be ported back by copying over.
But did not port them back any further than where they existed already.
Tweak a few related txt/html files also with trivial stuff like EOL-whitespace-removal.
Some applications, run on a CDROM, may attempt to open
a file with write access. CDFS driver will deny such
request in ReactOS (but also in Windows NT). Then, to
restore that behavior from old Windows (9X), our ntvdm,
as Microsoft ntvdm will attempt to reopen the file only
with read access, if opening failed because of denied access
and if the file is on a CDROM.
CORE-15211
