>but they are used as a proof such that the hash value of a clear text, like a name or perhaps even a future tweet (twat) from POTUS
Please don't state something like that if you're lacking knowledge about how 8kun works.
The hashes are sha256sums of the actual image file (its content).
As would for example be the case when Q saves an image from here, doesn't rename it, and re-posts it at a later point in time.
As a test, you can take any image, find its sha256sum, then post it here.
The image name given by 8kun will be that exact sha256 hash value.
…. or you can go on, believe whatever you want, sha256sum anything you come across and compare it to Q's image names.
Good Luck!