Helpmepls Yes I have been paying attention to the subreddit and the entire mystery. They have a section in their google doc on how people can help and stuff, it is pinned on the subreddit (so does the discord). Our article on the subject has been updated accordingly. Also someone on reddit asked if anyone has gone through old screamers to look for the image.
Currently, the oldest known screamer that contains jtk is NNN Special broadcast, made 2007. No other screamers contain the image before then.
Also don't click the link Quandale Dingle sent it's just a anne.jpg mirror if you haven't guessed already.