Attributing sources. Don’t remove!
It still shits me that people on Tumblr repost and remove source info but Tumblr makes it difficult / impossible for me to ask them to put the info back.
The most recent was http://jusdecanneberges.tumblr.com who reposted an image I scanned from Plats du Jour, or Foreign Food, 1957, Primrose Gray and Patience Boyd, Illustrations by David Gentleman and she removed the citing.
Respect the source. This is the reason I gave up on Tumblr.