Thumbnail (noun)

1. A small image or representation of a larger image, often used to help navigate through a collection of images.
2. A small version or sketch of something, typically done quickly or roughly.

Origin:

From the phrase thumb and nail, which refers to the small size of the nail on a thumbnail.

Examples:

1. The website displayed a grid of thumbnails for the different products.
2. He clicked on the thumbnail to see a larger version of the image.
3. The book included thumbnails of the artist's drawings.
4. He made a thumbnail sketch of the building before starting the final design.
5. The thumbnail view allowed for easy navigation through the document.