photo opportunity vs affair

photo opportunity and affair both are nouns.

Word	Noun	Adjective	Verb	Adverb
photo opportunity	Yes	No	No	No
affair	Yes	No	No	No

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

photo opportunity: an occasion that lends itself to (or is deliberately arranged for) taking photographs that provide favorable publicity for those who are photographed
affair: a formal or official social gathering or ceremony of people

Other hypernyms of photo opportunity include function, occasion, social affair, social function, social gathering, social occasion.

photo opportunity (noun)	affair (noun)
an occasion that lends itself to (or is deliberately arranged for) taking photographs that provide favorable publicity for those who are photographed	a vaguely specified concern
	a formal or official social gathering or ceremony of people
	a usually secretive or illicit sexual relationship