[Zope] Image Uploading

Hi, a new problem has appeared :-( Ok, I want to upload an Image into my ZOPE which only exists on an external Server. The pictures url could be http://somewhere.com/pic.jpg. So, I need a way, to insert this Image in my ZODB. But how, ... ??? I tried it with the manage_addImange tag, but without success. It seems as this tag only accepts files from my local file system. Perhaps, someone of you can help me, ... thank you, ... Marc