How to avoid Imagemagick's convert overlay of frames in a gif

Question

I have a bunch of files labelled 1.png and so on. I'm using the following command line to produce a gif animation:

convert -delay 20 *.png animation.gif

But the frames get superposed sequentially. I did not expect this behavior, what might be wrong?

Thanks

Answer 1

Option -dispose previous:

convert -dispose previous -delay 20 *.png animation.gif