I think one of the reasons this hasn’t become common (the concept and mechanism isn’t exactly new) is because of the massive complexity of trust relationships required to identify and validate the keys of “original trust sources”. Images and text get edited, resized, and transformed at a LOT of layers for a lot of reasons, and maintaining the chain of custody, especially with no authority to impose WHO is responsible for a compromised or forged key, is pretty unlikely.
I think one of the reasons this hasn’t become common (the concept and mechanism isn’t exactly new) is because of the massive complexity of trust relationships required to identify and validate the keys of “original trust sources”. Images and text get edited, resized, and transformed at a LOT of layers for a lot of reasons, and maintaining the chain of custody, especially with no authority to impose WHO is responsible for a compromised or forged key, is pretty unlikely.