There is a whole genre for miniature paintings. I just recently began playing with the concept. Although these are small paintings many may not officially qualify as "miniature paintings". For example, here's one set of rules that may govern miniature paintings for certain exhibits or shows:
"Miniatures should be painted to a scale of 1/6th life size or less. With regard to small objects such as insects and flowers this rule is flexible so long as the spirit of a miniature is retained in the work. i.e. the traditional method of stippling and hatching. Doll's house paintings should be 1/12th life size. In portrait miniatures, the head must not be larger than 2 inches [5 cm] including hair, wig, or hat. Faces and hair should be stippled and hatched, clothing may be painted more freely.The 2 inch [5 cm] size rule also applies to buildings, still-life objects and silhouettes.
I'm happy when I meet this simple criteria:
"The image size must not exceed 100 square centimetres, or 16 square inches." These pictures are approximately life size. A penny is included to give a better idea of the size of the painting. (I did not paint the penny.)