Hey Brad, if it is for the avatar under your name here, you can upload it to this site and it will give you the address here and you can paste it in. Just go to your profile and it will give you the options, make sure it is around 64 x 64 in size.
Is this is a pic just to display in a specific post? If so, please give the file name (it's case sensitive so it needs to be exactly what the pic was titled when you uploaded it.
If it's for an avatar, you need to be registered before you can use it I think.
I finaly figured it out, when i uploaded the file, I just typed in the file name, that won't work you have to load the file from the browsier or the compuer doesn't know where the file is. check out WISHFULL THINKING in edited screenshots