Question:
How do I set the transparent color in an TImageList so the
background color doesn't show?
Answer:
Use the TImageList.AddMasked(Bitmap: TBitmap; MaskColor: TColor)
method. You can either pass the transparent color yourself in
the second parameter or clDefault to let the imagelist take the
bottom-left pixel's color. TSpeedButton and TBitBtn use this
method. Check-out buttons.pas (around line 560) to see an
example.