Yeah, well, yet another Greasemonkey autocomplete script. If you go to Flickr’s Photos upload page, there’s no provision to select from your tags to add tags. Moreover, the default browser autocomplete obviously doesn’t understand Flickr’s space-delimited tagging. So when you type a character it’d provide you the entire set of tags that you might have typed earlier.
This script, on the other hand, has undergone rigorous training from folks at Flickrland and Monkeyland. After you type a space in the tags text box, the script will autocomplete for the character after the space. It’s kinda buggy, let me tell you. Get the script here. And don’t forget to set user_id—some-number@N00—in flickr_request().