Flickrfox embeds a photo stream on your Firefox interface, allowing you to review pictures from the popular photo hosting site. You can manage groups, keep in touch with your contacts and search for photos by using tags, all of it from the extension's sidebar.
In spite of being an original way to review photos, it feels a bit uncomfortable as there's little room for thumbnails (that is, if you don't want to lose too much web browsing space) and some pictures are almost indistinguishable.
Fortunately you can see the picture in actual size with a single click on the thumbnail.
Flickrfox's search function works fine but its configuration options are quite basic.