You can shove image data into fake pubkeys and while not cost effective(no use of Bitcoin for data storage is cost effective) it can be done. It really can’t be stopped and it doesn’t matter because running a node on a network designed the way Bitcoin is designed doesn’t make you liable for what’s on the node. By the logic that luke jr is using a person running a node that relays a financial transaction as part of a kidnapping ransom is aiding and abetting. It’s nonsense.