I'm looking for a way to make the the color black of my bitmaps transparent using GDI+. I know I was able to do that with GDI using this tutorial: http://winprog.org/tutorial/transparency.html Surely, there has to be a way to achieve the same result with GDI+?

Try using TransparentBlt or AlphaBlend functions in GDI or in GDI+,

http://msdn.microsoft.com/en-us/library/ms533798(VS.85).aspx,

you need to set the ImageAttributes.SetColorKey for the Graphics.DrawImage.