The easiest way is definitely, that you upload it on PB and just press right mouse button and find something like "copy IMG location". Press that one and then
Code:
[img]here click Ctrl+V[/img]
BTW: As we can see there are every month few threads with the same question. the easiest way would be if some mod would sticky this: http://pokebeach.com/forums/misc.php?action=help&hid=7
Or you could just try reading Noobnerd's Noob Guide when you get confused...
An easier way is requsting from the shop then they will give you the URL then in the "Edit Signature"Part of the User CP type in ["img]URL[/img] (remove the ")...