photo credit vs quotation

photo credit and quotation both are nouns.

Word	Noun	Adjective	Verb	Adverb
photo credit	Yes	No	No	No
quotation	Yes	No	No	No

As nouns, quotation is a hypernym of photo credit; that is, quotation is a word with a broader meaning than photo credit:

photo credit: a note acknowledging the source of a published photograph
quotation: a short note recognizing a source of information or of a quoted passage

Other hypernyms of photo credit include acknowledgment, citation, cite, credit, mention, reference.

photo credit (noun)	quotation (noun)
a note acknowledging the source of a published photograph	the practice of quoting from books or plays etc.
	a passage or expression that is quoted or cited
	a short note recognizing a source of information or of a quoted passage
	a statement of the current market price of a security or commodity