How to filter in image in an animated GIF?

I want to filter out part of a gif and add an image (i.e.: put a mask on someone's face in the gif) but also have the animation remain the same. Is there a way that I could do that?

ie: this gif: http://media.tumblr.com/tumblr_ln2nvmEyyK1qd4fop.gif

Answer 1

[Annie]

BUMP?.... i just need a yes or a no. and if its a yes, could you steer me in some useful direction.

[Jan]

Please do not post comments in the answer section. Bumping after 4 hours is not useful: When the readers do not know an answer, they do not know one 4 hours later, especially if you do not add any new information.

Answer 2

[Jan]

Yes, it works. Simply open the GIF, extract the frames, insert the modifications and save it finally. This sounds almost trivial, such that I assume, that you have not explained the actual problem you have with this procedure.