In reply to Ciprian.

I'm not sure that the WordPress media library default functionality is set up in a way that would match the type of "simple image searching" they're talking about. Flickr and other tools mentioned above have much more robust ways of handling those metadata fields and APIs for search tools that are already well tested.

Also, those sites are usually better positioned to host full size images than WordPress sites, where optimizing images to reduce load times is likely to be more helpful for overall performance.