> But my image is tagged as ProPhotoRGB. I think, before interpreting
> as sRGB, windows is supposed to do some gamut mapping from
> ProPhotoRGB to sRGB.
The tag is only used if the software is aware of it. Windows ignores embedded
profiles AFAIK. As I think Maris suggested, you'd need to convert the image
to sRGB in Photoshop then save it as a different name before using the new
file for wallpaper. Otherwise Windows will interpret the RGB values as
sRGB and they will look flat.
Rob Geraghty firstname.lastname@example.org