There are as many types of art galleries as there are types of art. In general, an art gallery has a specific focus, and is managed by a curator who specializes in that type of art. Common focuses for art galleries are art from a particular region, art in a certain medium, art of a singular style, or art which has a specific focus, such as political art. Typically, all of the art in an art gallery is for sale, although the gallery may retain a special permanent collection, or sponsor a unique display of art.
Most art galleries are public, meaning that anyone can walk into the art gallery and purchase art if he or she desires. Typically, public galleries host frequent openings and readily advertise their presence. Many artists get their start at public art galleries, which can sell work on commission or purchase work from an artist and resell it. Some art galleries, however, are private, meaning that you must be a member to enter. Private art galleries show high-end art, and sponsor lavish openings.
Many art galleries have curators which focus on art from a specific region or period. Examples of regions include European art, Australian aboriginal art, Chinese art, Asian art in general, or African art. Sometimes the regional focus will be extremely limited; a gallery might only show Peruvian textiles, for example. At other times, the focus is more general, and is designed to include a wide range of artistic styles from a general region of the world. In some instances, a gallery only features art from a specific period in history. This is especially common with contemporary art galleries, which display primarily modern art.
Commonly, art galleries will be dedicated to a particular medium such as furniture, oil painting, jewelry, photography, sculpture, textiles, or pottery. The medium may be specific to a region or time period, or it may be a more general collection of works in that medium. Usually the art on display is from a wide assortment of artists, allowing collectors of that medium to explore newcomers to the field and purchase a range of art.
Another common type of art gallery is a gallery which has a specific cultural focus. That focus might be political, historical, or medium based. For example, a gallery might choose to only display contemporary comic art. Another gallery might offer work by twentieth century Jewish artists, or display political artwork from African refugees. These galleries are typically open to members of the public, to encourage cultural education and enrichment.