comctl32: toolbar[1/4]: avoid using CopyImage as it doesn't work well when the DDBs are RGB565 (fixes bug #7905)

[Dmitry Timoshkov]

"Mikolaj Zalewski" <mikolaj at zalewski.pl> wrote:

> If the DDB format is RGB565, CopyImage uses an RGB555 intermediate DIB 
> that leads to data loses. This may change the COLOR_BTNFACE pixels 
> slightly and they won't be recognized as transparent anymore. As this 
> bug is also present under Windows, I haven't changed CopyImage but wrote 
> a new function that I hope works correctly.

Since it clearly sounds like a CopyImage bug it would be more appropriate
to fix CopyImage instead, Microsoft may do that at some point as well.

-- 
Dmitry.