I was reading this topic about users posting content to a community and not having the right to "take it down" later on. It got me to thinking about communities which might have a system to automatically pull in, say, images which are included in a post but hosted externally. The main reason the community might do this would be to prevent link rot and prevent holes in the discussion should the external copy of the image go away at some point in the future.
For example, a forum has a license grant that states that anything posted to the site is effectively licensed to the community, etc. So if someone uploads a photo, that photo is licensed to the site.
Would that same grant also apply to external images shown (not just linked to) in a post that are physically hosted elsewhere? Say, images the user owns which might be hosted in their flickr account, etc.
So could the community, in that instance, rightfully retrieve a copy of that externally hosted image and store it on the community's servers, and be protected against the user requesting deletion down the road, in the same way as if the user physically uploaded the file initially?