One still has to say that this is a bit unthankful for the uploader: The "Similar" buttons doesn't show any signs that this is a duplicate.
Well, for me it does. It shows another identical-looking thumbnail. Clicking it brings me to the larger post with Pixiv source.
Doing that much should be expected of an uploader. If someone can’t even be bothered to do that, possibly because they want to pointlessly “snipe” the post, they deserve to have their upload deleted.
I better ask if the function can be improved...
Like showing the image dimensions and source below the thumbnail? Nice idea, but only works if someone actually bothers to use it. ;-)