well you done goofed
Click the magic wand tool in Paint.net and click the background of the image (or whatever you wanted to make transparent) then press the delete button on your keyboard. Save it as a .png
You gotta save it as a .gif for it to be an avatar.
100% untrue
what.it worked for me.When I mean you need for it to be a .gif, that's if you want it transparent. If you don't need it transparent, make it a .png.