Learn in the textbookGUI Screen Controls, Menus, and Auxiliary Displays
DefinitionA thumbnail (サムネイル) is a small preview image that shows a picture or a document page scaled down.
ExplanationWhen many files are lined up, you can find the one you want by how its content looks instead of reading names. What you see is only a reduced preview, so to check details you open the original data.
AnalogyIn the days of film, people chose which frames to reprint by looking at an index print that showed every frame in miniature on a single sheet.
Memory hookThumbnail literally means the nail of your thumb, so remember it as a picture shrunk to about the size of a fingernail.