Crunch a Gif with Gif Cruncher
Crunch a Jpeg with Jpeg Cruncher
To see if your image is a gif or jpeg,
rightclick on image and look at PROPERTIES. There it will say if it's gif or jpeg.
If you are going to use lots of optimizing on your pics I suggest you purchase a lifetime membership for crunching
http://ejrs.com/optimizers.html
It will speed up your wait time and you can optimize a whole lot of them together.