You have to use some web service like tinypic or photobucket. tinypic is the easiest in my opinion. After you have uploaded it there, use the direct link that it gives you on the upload results page.
**•̩̩͙✩•̩̩͙*˚♫ and the haters gonna hate hate hate hate hate ♫**•̩̩͙✩•̩̩͙*˚