The phrase "tiny thumbnail" refers to an extremely small picture or image that represents a larger image, usually seen on websites or digital platforms. Full definition
As if that wasn't enough, you also want your cover to stand out and be legible in crowded pages of tiny thumbnail images. (mythotherapy.org)
Or in this case, squinting at teeny tiny thumbnails on stock photo sites and cursing their search parameters.) (mareeanderson.com)
That's hardly the case on the iPhone, where headlines look drab, story descriptions are cut off and pictures appear as tiny thumbnails. (tomsguide.com)