Firefox only: If you capture screenshots of web pages often and don’t want to go through the whole Alt-PrntScrn, Open Paint, Ctrl+C, Ctrl+S routine, the Page Saver Firefox extension’s for you. Save the visible portion of a web page or the entire page to an image in one click with Page Saver, which is great for reporting web site bugs or just snapping a web page pic for posterity. Page Saver’s got lots of configurable options, too, like the default filename for the image (with date variables for time-sensitive grabs), customizable keyboard shortcuts and a choice of PNG or JPEG file output format.
