Comment 2 for bug 381379

Maybe we can add instead of "GIF Transparency" checkbox, a more general "Transparency" checkbox which is True by default. Phatch would behave like this:
1) Transparency = True
- gif: transparent =1 is passed to the save function
- png: normal pil save
2) Transparency = False:
- gif: normal pil save
- png: if image is rgba, it is converted first to rgb and then saved

Phatch is aimed also at not very graphic experienced people. They know what transparency is, but not what RGBA means.