Strange bug

[William Ramsay <ramsayw1 comcast net>]

Can anyone explain this?    I am working with gtk via Chicken scheme, 
but have reproduced the problem in C.   I am writing a small icon 
drawing program that uses Imlib2 to save the image.    When I save a 
transparent PNG image the image ends up with random garbage pixels in 
the transparent area.   If I use exactly the same Imlib2 save code 
without gtk in the program, there are no bad pixels.  What the heck is 
going on?

Bill