That's why I was thinking it would work better as a separate thing where you nominate images / gifs as being good candidates for appearing in the image picker. This would also allow for multiple people to add tags to a given image.
Discussion
Cool part about a database like this, is, its effectively immutable. A file will always have the same hash, so once tages have been set, they never need to change.
I wrote a note a couple weeks ago about malware detection on blossom with essentially the same purpose