I've never used that second section in the Manage Attachments. It's not going very well. OK, from flickr, you have to navigate to "download the large (larger of the medium sizes would be better) size of this photo". Of course, the file name is ugly. I don't seem to be able to attach a photo from the forums, though I am linking to them on the vcbf map now. Our map person had to make a change to the dialog to accept the url format.