Prevent image cropping when making sprites from gif

Hey guys I've tried several tools (imagemagic, gif2png, Nconverter) to extra开发者_运维百科ct frames to make sprites from a .gif image that i have.

I get the .pngs just fine, but they'r not the same size, some are 50x65 some 43x65 some 50x70, Which really screws any attempts at a descent animation. So is there a way to prevent this cropping or programmatically add extra transparent space to smaller ones and make them all the same size?

Thanks.

I'm not sure you're looking for a programming solution or an application that will extract the frames for you.

MPlayer can extract the frames of an animated .gif into a series of PNG files using this command:

mplayer test.gif -vo png

I'm pretty sure it will keep a constant output frame size throughout the animation.