Zubair007 A GIF image (static or animated) shouldn't be handled any differently from any other image, which are frequently used (and even encouraged) for publishers.
After the first fetch of a page with images on, Ezoic should be able to cache the image along with everything else, meaning that it will load more quickly for subsequent users.
So long as the image is optimised it shouldn't be an issue. That is assuming that GIF is the best format choice for the type of image you are trying to display (generally low color diagrams/drawings etc. work better than photorealistic images, for example).