It is best the the gifs are in Tumblr or Photobucket. For tumblr gifs, it is simply right clicking the image and selecting the 'copy image url option'. In photobucket, upload the gif then get the direct url link from the links box in the right side panel of the page. Then in the toolbar of AFF's text editor, click the image icon. A box will appear. Paste the url on the space. Hit ok. Or you have done all this and still doesn't work?