Ever been stuck waiting, and waiting, and waiting some more for photos to upload? Short of getting a faster connection there's not much you can do with big image files. You can go the software route, and download something free and simple like Paint.net to do the resizing pre-upload, but you don't always have time to do this with every shot, and if you're like me you're kind of lazy.
Enter Shrunked, a great new extension for Firefox. It lets you resize a photo before uploading it. It works anywhere that doesn't use a Java applet or snazzy Flash uploader (so no Facebook or Flickr via their multi-image uploaders). When the extension detects that you're trying to upload photos it gives you the option to resize them to one of three presets, along with a custom size where you can set the width or height while keeping the aspect ratio the same.
There are several uses for this, with one of the best ones being profile photos for social networks. Most of these sites have resizing tools on the server side that will do the same thing, but again if you're on a slow connection, waiting for that 5MB or 6MB file to get there can be a drag.