Thumbstrips is a wonderful Firefox extension that helps you view recently visited web pages in a visual manner - it's a more user friendly and powerful approach than the native Firefox History view (Ctrl+H).
Thumbstrips, like an automatic screen capture program, takes screenshots of the websites that you are visiting and also records other details like how long you stayed on that web page and the number of times you viewed that page in your current session.
With recording turned on, press F2 and the website thumbnail images will display as a filmstrip in chronological order - move your cursor over the thumbnails to browse through your web history or right click any image to get more details about your interaction with that particular webpage.
Since thumbstrips will also save the associated HTML source code of web pages, you can use it for searching the browser history with keywords that may be in the title, URL or body of the webpage. The thumbnail images can also be saved to a local folder or shared with friends.
And Thumbstrips will save a snapshot of the webpage as you see it in the web browser - not the entire webpage which could span several folds.
I was expecting Thumbstrips to consume tons of memory since it is always processing in the background but fortunately, that's not the case. Give it a shot.How to Capture Web page Screenshots