It's a MLP booru, dude

Imgur has been used in the past by several artists to store higher res images due to Tumblr (and some other sites') resolution limits; I am not intimately aware of their optimization policies, but I assume their system ran some analysis and decided converting the image to a JPG would be beneficial (for them).The uploader did not make a mistake; they have no access to the PNG in any form and no way to know that the JPG offered on Imgur by the artist isn't the "ultimate" file. In any case, a 2000x1000 JPG would still be superior to a downscaled PNG half the size (unless the artifacting were really bad)."Background Pony" is the site's terminology for "Anonymous", given to users that do not have an account on the site, or that do but prefer to not be identified in the upload credit or comment (for whatever reason, like not wanting to be known for uploading porn, or not wanting to be confused for the artist).