It is possible to do that using GDI+, but it needs to use some functions that are not present in _gdiplus.vcx.

Basically we need to use GdipLockBits, GdipUnlockBits, GetColorPAlette, SetColorPalette, and convert the image pixels. In www.bobpowel.net there's another example using VB .NET.

I'll wait until the new classes from VFP-X project are released to translate an example.