A cabinet painting (or "cabinet picture") is a small painting, typically no larger than about two feet in either dimension, but often much smaller. The term is especially used of paintings that show full-length figures at a small scale, as opposed to say a head painted nearly life-size, and that are painted very precisely, with a great degree of "finish". From the fifteenth century onwards wealthy collectors of art would keep such paintings in a cabinet, a relatively small and private room (often very small indeed, even in a very large house), to which only those with whom they were on especially intimate terms would be admitted.
This room might be used as a study or office, or just a sitting room. Heating the main rooms in large palaces or mansions in the winter was difficult, and small rooms were more comfortable. They also offered more privacy from servants or other household members or visitors. Typically, such a room would be for the use of a single individual, so that a house might have at least two (his and hers) and often more. Names varied: cabinet, closet, study (from the Italian studiolo), office and others.
Later such paintings might be housed in a display case, which might also be called a cabinet, but the term cabinet arose from the name (originally in Italian) of the room, not the piece of furniture. Other small precious objects, including miniature paintings, "curiosities" of all sorts (see cabinet of curiosities), old master prints, books, small sculptures and so on, might also be in the room.
There is a rare surviving cabinet with its contents probably little changed since the early eighteenth century at Ham House in Richmond, London. It is less than ten feet square, and leads off from the Long Gallery, which is well over a hundred feet long by about twenty wide, giving a rather startling change in scale and atmosphere. As is often the case, it has an excellent view of the front entrance to the house, so that comings and going can be observed. Most surviving large houses or palaces, especially from before 1700, have such rooms, but they are very often not displayed to visitors.
The magnificent Mannerist Studiolo of Francesco I Medici in Florence is rather larger than most examples, and rather atypical in that most of the paintings were commissioned for the room.