Sounds like a bot that alerts its operator when it gets a (You).
8chan filenames are SHA-256 hashes of the image file contents. And it's not (practically) possible to contrive a file to produce any specific result from this hash function. You're looking at randomness.
I looked in to that closely. They are about as big as they should be given that they are typically photo type images stored in a lossless format designed for images with contiguous uniform areas (not photo) images. A PNG is like a a BMP in a ZIP file. And they have HUGE resolutions.
They seem to be screenshots from a iPhone.
Anything kept hidden can happen again. The only thing to keep it from happening again is for future generations to be forever vigilant of it. It must become public knowledge in due time.
They didn't shy away form anything at the Nuremberg trials.