While I was dicking around in the page source of a deleted post, I found a link that should look like this: "https://e621.net/comment/atom/ (post id)". As the link suggests, it showed me all the comments linked to the post in a new tab. However, within the details of the comment, I found the image source (y'know those "static1.e621.net" pages that show up when you open an e621 image in a new tab? Yeah that one).
Here's the thing: it shows only the THUMBNAIL of the pic, not the whole thing. There also needs to be at least 1 comment for it to work. Here's an example: https://e621.net/post/show/1137047/
As you can see, the post is deleted. Now if you go to the page source, you will find this link: https://static1.e621.net/data/preview/4c/e5/4ce53d1e4e18b12d0e2d562d31e5380d.jpg
idk what to do with this info so i'll just throw it out there ¯\_(ツ)_/¯
If you wanna check if the thumbnail is legit, go to the furaffinity source (http://www.furaffinity.net/view/22500368/)
(my first forum post so yay)
Updated by hello world