stock image vs photograph

stock image and photograph both are nouns.

Word	Noun	Adjective	Verb	Adverb
stock image	Yes	No	No	No
photograph	Yes	No	Yes	No

As nouns, photograph is a hypernym of stock image; that is, photograph is a word with a broader meaning than stock image:

stock image: an existing photograph licensed for a specific use
photograph: a representation of a person or scene in the form of a print or transparent slide or in digital format

Other hypernyms of stock image include exposure, photo, pic, picture.

stock image (noun)	photograph (noun)
an existing photograph licensed for a specific use	a representation of a person or scene in the form of a print or transparent slide or in digital format

stock image (verb)	photograph (verb)
	record on photographic film
	undergo being photographed in a certain way