Make your own animated gif free
Make A Gif - Animated Gifs Maker, Free Gif Creator Online
I didn't see a way to create the size, but I imagine you could create the size you want in GIMP or something and add your image to the canvass/template. Create a xcf/psd "template" and create the individual images. BTW with the Opera browser I could only add the images one at a time, but it worked.