Wow, really? I've always been told, and grew up knewing from everyone that if a horse has white markings (other than the normal stockings/face markings) than it is a paint. Doesn't matter if it's the breed or not, white means paint reguardless of how you look at it. So how does that work, because, again, totally different than how I grew up??
This article explains it better.
Paint vs. Pinto
What is the difference between a Paint Horse and a pinto horse?
Q: What is the difference between a Paint Horse and a pinto horse?
A: Paints and pintos have one thing in common: a flashy coat featuring patches of white and a solid color, such as bay, black or chestnut. Beyond that, there are many differences. For one, a Paint Horse is a breed that, according to the American Paint Horse Association (APHA), "has strict bloodline requirements and a distinctive stock-horse body type." Paint Horses can only have the bloodlines of Quarter Horses, Paint Horses or Thoroughbreds in their pedigrees. In order to qualify for registration with the APHA, their sire and dam must be registered with the APHA, the American Quarter Horse Association or the Jockey Club (the breed registry for Thoroughbreds).
On the other hand, "pinto" is a term that refers to the colorful coat pattern and is not the name of a particular breed of horse. Any horse of a breed other than the Paint Horse that displays one of several coat patterns is considered a pinto. Breeds that commonly produce pinto horses include the Tennessee Walking Horse, Gypsy Horse and Miniature Horse. Breeds such as the Spotted Saddle Horse and Spotted Draft Horse are exclusively pintos.
There are two main registries for pinto horses—The Pinto Horse Association of America and the National Pinto Horse Registry—and each separates pintos into categories depending on their breeding and conformation. The Spotted Saddle Horse Breeders and Exhibitors Association, National Spotted Saddle Horse Association and International Pattern Sporthorse Registry also accept pinto horses. The Pintabian Horse Registry specifically registers pinto horses with primarily Arabian horse breeding.
Pintos are described by their coat pattern. The two most common patterns are the tobiano and overo. Horses that display characteristics of both patterns are considered toveros. There are also several other pattern types, but that's another whole article in itself!