art gallery vs picture gallery

art gallery and picture gallery both are nouns.

Word	Noun	Adjective	Verb	Adverb
art gallery	Yes	No	No	No
picture gallery	Yes	No	No	No

As nouns, art gallery and picture gallery are synonyms defined as:

art gallery and picture gallery: a room or series of rooms where works of art are exhibited

Other synonyms of art gallery include gallery.

art gallery (noun)	picture gallery (noun)
a room or series of rooms where works of art are exhibited	a room or series of rooms where works of art are exhibited