SearchPreview for Firefox provides a thumbnail preview to your search results. Also available for Chrome.

This add-on is designed to help enhance your search result pages by inserting preview images as well as popularity ranks.

SearchPreview for Firefox inserts site preview images (thumbnails) and popularity ranks into Google, DuckDuckGo, Yahoo and Bing searches. SearchPreview for Firefox does not process or retain personal user data and only handles non-personal user data that is required for its features to function. If you turn off the features, no user data is transmitted or held. You can also use it for verifying that the site you are about to go to looks as it should possibly thwarting you ending up on a page that has a similar name to the one you intended to open.