A lot of people have a nebulous understanding of the different types of venues art is shown in.
The simplest way to think of this is:
Museums, like the Dali or Museum of Fine Arts, show work, either from their permanent collection, which they own, or a visiting exhibit, which someone else owns. These works are not for sale, and Museums charge admission for the public to see them in order to stay in business, and have gift shops, restaurants or cafes as well for other revenue streams.
Galleries, like Mindy Solomon or C. Emerson, show work from a multitude of carefully vetted artists, in conjunction with a theme, some of which they may represent. Representation means the gallery acts as an agent in the promotion and sale of the work within certain contractual limits. All the art in a gallery is usually for sale, and the gallery gets a commission from that, which is how they stay in business. Galleries sell the art, but normally do not charge admission for people to see it.
Co-ops, like Tampa Artits's Emporium or Artpool charge the artists rent for the space their work takes up, and often also take commissions when the art is sold. The artists are not nearly (if at all) as stringently vetted as they are at the galleries. Paying rent is the main qualifier. Co-ops frequently have parties, which also bring in income. Some, but not all, charge admission. While they have openings, and sometimes bring in new artists and themes, one sees mainly the same artists there.
Cafes & Others - Cafes, like The Globe, Kahwa, Or Bohemia operate a lot like galleries. Since art sales are not crucial to the financial well-being of the operation, arrangements often vary.