Video files, vector and raster images, raw camera images as well as documents may contain metadata identified with the designation Thumbnail Image. In some cases, the metadata may be located in other files of the same kind as long as they contain images that could be represented in thumbnails.
For photographs, the thumbnail includes a smaller version of the real image. For video, a still image taken from the streaming video is generally utilized. In the case of documents, pages are usually depicted as an image to be used as a thumbnail.
The information provided by those who are able to access the Thumbnail Image is structured in an orderly manner. The first portion identifies the type of data used to create The Thumbnail Picture. Most often, it's binary data. The second section is the dimensions of thumbnails in bytes.