Linking to external sites subjects to link rot.
Is it a good idea to host all such images on imgur and add a footnote citing the source of the image?
Linking to external sites subjects to link rot.
Is it a good idea to host all such images on imgur and add a footnote citing the source of the image?
Yes, but you should make sure you use the tool in the editor - As this will go through Stack Exchange's pro account and the images will not expire.
http://blog.stackoverflow.com/2010/08/new-image-upload-support/
We should convert all images to imgur links, but we should also add an Important notice! for image identification requests saying that the image link must be provided as it is on where the OP found it, so it would improve the chances of finding the source.
Images often have title, character or artist name in the url. Can't allow that to go to waste.