How to extract frames from a GIF file preserving frame dimensions

Question

I have the following GIF image file:

I want to extract its frames (using PGM output

Answer 1

You can use graphicsmagick:

gm convert Test.gif +adjoin Test_image%3d.png

or

gm convert Test.gif -coalesce +adjoin Test_image%3d.png.

Answer 2

Use the -coalesce option:

convert -coalesce brocoli.gif out%05d.pgm