This might be by design. Under the Using Image Lists section in the msdn it
The ILD_BLEND25 and ILD_BLEND50 styles dither the image with the system
highlight color. These styles are useful if you use a masked image to
represent an object that the user can select. For example, you can use the
ILD_BLEND50 style to draw the image when the user selects it.
ILD_BLEND and ILD_BLEND50 are the same thing, BTW.
MS MVP Visual Basic
: I've been trying, without success, 'blending' alpha-icons with custom
: fore color ([rgbFg])... Yes, trying this on XP and with manifest file,
: etc. Alpha is correctly rendered in other cases, but what I get with
: ILD_BLEN25 or ILD_BLEND50 styles, is simple a semitransparent icon (25% or
: 50%, blended with background). Same results with ImageList_DrawIndirect.
: And strange thing, this effect seems working "OK" in IDE (well, without
: taking in account that alpha is not rendered correctly, and that this
: is got through a pattern brush). I don't think this has nothing to do with
: alpha-icons, because, when no custom rgbFg color is specified, and style
: set to ILD_BLEN25 or ILD_BLEND50, effect is applied correctly using
: system highlight color.
: Any ideas? Is this a bug, or a "limitation"?