wedding picture vs photo

wedding picture and photo both are nouns.

Word	Noun	Adjective	Verb	Adverb
wedding picture	Yes	No	No	No
photo	Yes	No	No	No

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

wedding picture: photographs of bride and groom and their friends taken at their wedding
photo: a representation of a person or scene in the form of a print or transparent slide or in digital format

Other hypernyms of wedding picture include exposure, photograph, pic, picture.

wedding picture (noun)	photo (noun)
photographs of bride and groom and their friends taken at their wedding	a representation of a person or scene in the form of a print or transparent slide or in digital format