We usually snapshot or screenshot of different things on our desktop / mobile devices as per applications use, but for taking a full screenshot of entire webpage is difficult as it depends how long is it. Also if you want to know how your web site looks in other browsers and other operating system with various options of gadgets then you must use following tools.
Browsershots.org capture screenshots of your web design in different operating systems and browsers as per mentioned in list. A free open-source online web application providing developers a convenient way to test their website's browser compatibility in one place.
Just submit your web address, it will be added to the job queue. A number of distributed computers will open your website in their browser. Then they will make screenshots and upload them to Browsershots.org's central dedicated server for user review.
You may choose different browsers with different options that you want to test your webpage. You may select different options from the list and test them as per your requirements.
Cons : No Mobile Web-Browser Testing Supported right now.
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Browsershots.at is normal screenshot capturing utility which provides screenshot of webpage as displayed in Firefox on Windows Vista system. This is old technique and mostly screenshots from firefox are captured.
Screenshot will be generated in size of full resolution of 1024×768. Browsershots.at provides screenshots of websites in testing environment which allows you do uncover serious html or css faults too.
Cons: Only Firefox browser testing on Windows Vista os.
This is the most used and advanced tool available online as free which provides wide variety of testing of your webpage in many browsers on different devices including Smartphones, Computers, Mac too.
You just have to put the URL, choose the appropriate settings that you want to have in your screenshots like Quality, Resolution and mobile layout too and Browserstack will do rest of the work for you.
There are variety of browsers available with different versions list helping you to choose right one and so you may make your website better. There is history button to let you cache your previous screenshots easily.
Although the service is free but if you want to test web or commandline tunnel than you must be registered user in Browserstack.
Cons: Nothing as We don't found any !
We compared all 3 above services and we will say that, if you want to thoroughly test your webpage in different browsers and on various devices including smartphones then you must go with Browserstack and if you want to get screenshots of website for only Computer related operating systems then Browsershots.org is best at its own and finally, if you want single screenshot of a webpage then use browsershots.at.
Hope now you are able to take full screenshot of a website.