If you want to take a screenshot of your current browser window, there’s always good old ALT-Printscreen, but this function captures the whole window, not just the contents, and copies it to the clipboard. Then you still need to open a graphics editor, such as Paint.Net, to crop, edit, and save the image.
There are, however, a couple of browser extensions to simplify the process, and support capturing the complete page contents, rather than just the visible part of the page.
Here’s the list of extensions I use:
In Firefox, I use Screengrab (fix version). It allows you to save or copy-to-clipboard the complete page, the visible part, or a selected area of the current page.
In the settings, you can define the pattern of the file name of the saved image (default: HTML Title and timestamp), and the text that is generated at the top of the image (default: URL). The option “Quickly save” won’t prompt you for a file name.
I love this extension for Firefox – however, if the screenshot gets too big (about 1.5Mb on Win32, 3Mb on Win32), it silently fails and generates .png files of size 0).
The extension Screen Capture (by Google) is now unsupported, and it did not work (read: the menu buttons did not invoke any recognizable action) on the latest versions of Chrome.
The extension Awesome Screenshot: Capture & Annotate supports capturing the complete page, the visible and a selected part of the page. After capturing, a simply picture editor allows you to crop the picture, or add simple graphics and text to the image. The file name of the saved image defaults to the page’s Title, but can be edited in the Save As dialog.
Unfortunately, only the command “Capture visible part of page” works on Facebook pages – both “entire page” and “selected area” fail to capture.
Finally, the extension Full Page Screen Capture simply generates an image of the complete page, and displays it in a new tab. From there, you need to invoke Save (ctrl-S) to save the image to the default directory. File name pattern is “screencapture-” plus the current URL. This extension provides no options.