You can only upload .gif and .png files on Era. I know .mngs have fallen from popularity, but I figured out how to make them (patent pending, Ancient Chinese Secret), and how to do some cool things with them that .png and .gif just can't do (variable transparency, animated glow effects, shadows, etc.).
Pretty much nobody uses it, but you might as well white-list it for advanced users who might, right?

Make this happen, and I can make some damn cool player graphics.