A thumbnail image is a small image that represents a larger one. Thumbnails are often used to provide snapshots of several images in a single space. They are commonly used by digital photo organization programs as well as visual search engines.
The term "thumbnail" was originally used to describe physical images or drawings that were miniature in size (roughly the size of a human thumbnail). However, it is now widely used to describe digital images, which are displayed on a screen. Digital thumbnails are usually between 75x75 and 200x200 pixels in size. They can also have a rectangular aspect ratio, such as 150x100 pixels.
Since digital thumbnails represent a larger version of the same image, they also usually serve as a link to the larger image. For example, clicking a thumbnail on a Google Images search results page will open the page that includes the full size image. Similarly, double-clicking a thumbnail image in a photo browser will usually display the full size version.
Thumbnail images may also be referred to as "thumbs."
Updated: June 4, 2010