I am using imagemagick's convert to take a set of PNG's and convert to GIF. The command I am using is
convert -delay 10 -loop 0 *.png out.gif
I like the results as there is little drop in visual quality, but an issue I've run into is when my PNG's have transparent data: each frame doesn't seem to be a separate picture, but instead anywhere that was transparent you could see the previous images' data.
So for example if you have a ball rolling from left to right and the background was transparent, you would see all of the previous frames where the ball was at.
How can I deal with this? I would like the GIF to preserve the transparency if possible (otherwise, just make it a pre-defined color), but I would like a proper animation.