core + attic (Attic Area): these terms have been either depricated from the core or extentions, or removed from pending as not accepted into the full vocabulary.

thumbnail

Canonical URL: http://schema.org/thumbnail

Thing > Property > thumbnail

Thumbnail image for an image or video.

Usage: Between 10,000 and 50,000 domains
Values expected to be one of these types
ImageObject
Used on these types
ImageObject
VideoObject

Schema Version 3.2