Google preview is an add on for firefox users which enables images of the websites to be previewed together with the website link and description at the search result page. Before this, if you search for a word using google, you will arrived at the search result page with websites link and description. However, you will never know how is the website look like unless you click on it and visit it. With google preview, you will have an insight of the website before visiting it. Look at the screenshot below. It explain how google preview work.

Many people think that google preview only work for google. But actually, this add on also work for yahoo. So if you search using yahoo search engine, you will see images shown together with the description and the link of the website at the search result page.

I have personally tried out this brilliant add on from firefox and it is really great. Everytime when we want to click into a webpage at the google search result, it is like opening a door but don't know what is inside. With google preview add on, it provides us some insight or clue about the webpage.

Up to date, there are about 2,703,663 total downloads and quite many internet users give a thumb up for it. It does'nt slow down your internet speed and i haven't face any bug before.
So I suggest you to give it a try if you haven't install it..Click this link to go to the official download page.