Anons,
Finding the raw photo is good. Legalanons can advise on how one might compel Getty to release it. Also, many media sources that published the photo may have received a .RAW TIFF file. If we can get a hold of one of those it would be interesting.
However we might only be able to prove that Getty doctors their photos. The .RAW file should be easier to analyze because there is no JPEG artefacts, but at the end of the day, there may only be a doctored photo.
This is why the video is key. Even if there is only one original in the hands of the FBI, using FOIA to get it puts more eyes on the analysis. A video is harder to doctor.
And, if the person really was writing a message, then even if the message has been replaced, the video will show their finger taps which lets us recover the message. Just like those old 30s movies where the detective unrolls a typewriter ribbon and reconstructs what was recently typed. It's called forensic investigation, CSI, etc… You can do it too.
Need some advice from legal anons. Know a lawyer? Get them to join in this conversation. They can even use your computer to write their messages if they are afraid of the watchers.