Why do my gifs become slow after editing them in Photoshop Elements 7?

I have a few gifs I'm looking to edit. Mostly crop, but there's one or two I would like to delete the last few frames from. I was wondering why every time I do these things in my Photoshop Elements 7 the gifs become really slow. Is there a certain way I need to save them? Or can it just not be done in Photoshop Elements 7?

I'm not looking to download any programs, free or otherwise.
 
Back
Top