Maryland_P_Sevenson said:
specifically it seems like it's something that happens to images that are jpegs uploaded to Twitter that are 2048px tall. but only sometimes... some artists seem to have it happen almost all the time whole most artists don't seem to have it happen at all.

You mixed up your link, the destination goes first.
And yeah from my experience it's pretty common with files from twitter

Also I bet you're referring to spicykiwi's (plush) stuff which has frequently become a victim to the effect. Speaking of, should we make a tag for it? (Or at least an umbrella tag for site forced visual errors that aren't generic stuff like compression)