there is a trick to the external link thing however, I think you go to your hosted site and bring up the image in question then right click on it and look at the properties of the image, Now you copy (CTRL-C) the address in the Address or URL portion and then paste it (CTRL-V) into the image popup window portion as "He who shall remain nameless" said.
I will try it right now with your nano reef zoanthids
the address to your pic is of course all the http stuff and then community . webshots . com/rz/r1/3/62/95/27036295eVIRnpGerK_ph . jpg
I added a bunch of spaces here and there in what I just typed here so the bot would not auto convert into a url but you should get the idea