I’ve been using Pearl Crescent Page Saver Basic for over a year. It lacks an editor, but it’s easy-to use and allows you to save Web page images as JPEG or PNG files. You can scale the output image, format the file’s name, and capture Flash content.
Using the plugin’s button, located on Firefox’s Navigation Toolbar, you can easily capture the visible portion of Web page that’s currently displayed or the entire page. You can also configure a keyboard shortcut for taking screenshots.
Note: Click each image for a full-size version.