If you end up doing mass tag metadata importing, I'd recommend making it so it can only add tags and not remove them. Some buttmad idiot removed the 4chan tag from a huge number of images because "ThAt'S WHaT the SoURce SEArch iS fOr", completely negating the fact that there's dead threads and several archives. Not to mention that's literally where these are coming from and not the artist's personal gallery of any kind.