I like your way of thinking. This isn’t even limited to image. Comparing just a short snippet of the audio from a playing ad to a db could work very well too, thinking of how quickly Shazam etc. are able to identify a song if it’s in the db.

App/plugin idea for the sad future right there: Shazadblock, tuneBlock Origin. Succesful ID leads to skip/mute/ragequit or whatever will kill the noise. Though, the downside of this method would be if an ad in the db uses licensed music that regular content creators use in their videos too, it will eventually lead to blocking some segments wrongly, unless the db excludes this, making it less effective at its purpose… Maybe image is better.