Whether or not there are copyright issues depends on the laws of specific countries. In general though it's a lot more legal than currently legal things like Go

Whether or not there are copyright issues depends on the laws of specific countries. In general though it's a lot more legal than currently legal things like Google Image Search, because it's much more transformative than making thumbnails of other people's images is. But if you don't want it to be legal then just pass a law saying it's not.