You can readily create a bitmap from the binary data that's read in from a file (via a simple binary FileRead) using _GDIPlus_BitmapCreateFromMemory(). But how do you do the reverse?  That is, to generate/copy the binary data back from the bitmap so that it's the same as if you performed a binary FileRead()? After reading all kinds of things on this issue, both here in the AutoIt fora and non-AutoIt sources elsewhere, I still haven't been able to find the answer. At first it seemed like _GD