
Dillocircus 
Moderator
cub appreciator
Yeah, I noticed the Pixiv thing too, though I chose not to bother Pup, as they seem to be quite busy otherwise. I think the animation thing is because animations on Pixiv are literally not animation files, but instead separate images for each frame with a JavaScript cycling them.
A useful trick is to copy the image (not save, literally right-click → copy image), because you can then paste it directly into https://saucenao.com/ and use it to check whether the image has been uploaded to e621/rule34, and then possibly upload from there instead.