Do you people just upload and never browse Danbooru (or at least use "find similar")? This was uploaded just yesterday.
Uploaded from a different source. People who upload loads of pics don't always bother checking every image before doing it. (Heck, manually checking thousands or tens or thousands of pictures some uploaders have uploaded would slow things down and drive uploaders insane). I think that they use macros or something anyway.
I'd assume it causes more "slowdown" to upload two copies of a picture to our database than it does to upload one and do a thumbnail search on the other (which is what Find Similar does).
Checking for similar should be part and parcel of uploading hammer's work at this point just because of how many times the exact same picture gets uploaded since he posts to both pixiv and nico nico.
Checking for similar should be part and parcel of uploading hammer's work at this point just because of how many times the exact same picture gets uploaded since he posts to both pixiv and nico nico.