Owen, unless you know what you are talking about, please do not say anything. If anyone were to right-click right now on Raebus's avatar and save the image, the filename would end in .jpg. It is a .jpg. This cannot be argued.
Raebus, there are two fixes for this:
The first is the hard way, which would be to reopen your avatar's file, rasterize the layer, select the entire background and delete it, and then go back over your image, re-doing the color palette because of artifacts and color bleeding. Then, instead of saving, make sure that you select "Save As..." and make sure that the second box "Save as type" has .gif highlighted. Give it whatever filename you want and you are gold.
The second is a bit easier if you can do it. If you have kept a previous .psd or .pspimage file of your work (I recommend that you start doing so if you do not!), simply reopen that file and if there is no editing that you need to do, save that as a .gif.
Always try to remember that throwing on ".gif" at the end of a file that you are saving does not guarantee that you are saving it as a .gif; that second box in the Save dialouge box does.
An attachment too, for a visual aid as to what I am talking about.