Image->Canvas vs. Bitmap->Canvas Transparency

I have a small bitmap which requires transparent background. It can be
copied to an Image->Canvas with no problem (transparency works OK). But
when I copy the same bitmap to a Graphics::TBitmap Canvas the
transparency is lost. Is this a known difference between TImage and
TBitmap? Is there a workaround, or an added step required?

There are two things you must never attempt to prove: the unprovable --
and the obvious.