Einstein, The World's Smallest Miniature Horse

Worldwide, there are dozens of miniature horse registries. Some organizations emphasize breeding of miniatures with horse characteristics, others encourage minis to retain pony characteristics.
The AMHA standard suggests that if a person were to see a photograph of a miniature horse, without any size reference, it would be identical in characteristics, conformation, and proportion to a full-sized horse.
According to the AMHR, a "Miniature should be a small, sound, well-balanced horse and should give the impression of strength, agility and alertness. A Miniature should be eager and friendly but not skittish in disposition."
Miniature Horse Club Great Britain (MHCGB) is able to register and issue passports to miniature horses with 50% or more American blood, at least one parent must be registered with the AMHA.