Sometimes images on sites such as Facebook, Amazon or Wikipedia are too small to see all the details of the image. And while there is often a way to click on the image to load a larger version of it on a new page, it is not really the most comfortable experience, especially if there is more than one to look at.

This is especially true for shopping sites like Amazon were the results listing is displaying the item images in small thumbnails. It takes a few clicks to see a larger version of the item on the site, which for me means wasted time.

The Firefox add-on Thumbnail Zoom Plus comes to the rescue. It is a free add-on for all recent versions of the Firefox web browser that adds a zoom on hover option to the browser.

Just hover the mouse cursor over an image on a supported website, and you are presented with a larger shot of the image on the same page. The larger version is displayed in an overlay on the screen, and removed again once you move the mouse away from the image. It is alternatively possible to press the Escape key on the keyboard to hide the overlay again.

This often allows you to see details that you would not otherwise be able to see without clicking on the image to load the larger version of it.

The add-on works with several of the most popular sites on today’s Internet. From Amazon and Facebook over Pinterest and Twitter to Wikipedia and IMDB. Plus, it is also compatible when images are linked directly on a site.

A popup image is only shown if it is at least 20% larger than the regular image that is displayed on the site you are currently on.

The preferences allow you to change some of the features of the extension, for instance to change the delay before the larger image is shown, or the option to disable the extension on select sites.