avalanche123/Imagine — pull request #140 by romainneutron (2012-07-19 16:54:50+00:00)
Title: Fix PNG transparency on save ; do not flatten if not necessary

In avalanche123/Imagine#132 I force the flatten operation before saving for all image.

This introduced a bug : PNG with transparent background now got a white background when saving.
This PR fix the introduced bug by checking if the image is multi-layered before flatten it.