One of my readers, using firefox browser, asked me which is the best and easiest way to capture screenshots of a web page without using any software or any online tool. And I have been using this tool in firefox browser, an add-on that helps me capture screenshots of web pages, and save the captured picture locally.

Its Screengrab firefox add-on! – Check the firefox add-on page.
It will capture what you can see in the window, the entire page, just a selection, a particular frame… basically it saves webpages as images – either to a file, or to the clipboard. There are a couple options, like either copying the image, or saving it. Also it can be the entire web page or just the visible portion.
It also has an option of selecting a particular portion of the web page and saving it as a screenshot. The image gets saved as a .png format unless you specify any other format.
It can capture any Java or Flash embedded in a page, but to do this it requires Java to be installed in the browser.

You just have to open any web page, and then click on the Screengrab icon in the right bottom of the browser, with many options where you can select the desired one –

Here’s a screenshot taken of the entire web page, for an example –