Many of my favorite illustrators did a lot of Western-themed pictures. Most of these artitsts were from the mid-20th century, when the romance of the West was still strong in the book and magazine world, and many of them could make a living on commercial art centered on Westerns. And perhaps more to the point, many of them actually had ranch backgrounds. Here's a very small sampling of great equine illustrators' takes on what is probably the quintessential Western image - the bucking horse.
C.W. Anderson, Sketchbook
I tend to associate Anderson with the East due to his many Thoroughbred racehorses and jumpers, but he was born in Nebraska and he had a flair for action, whether it was the sunfish of a rodeo star or the surge of a steeplechaser.
Lorence Bjorklund, Gentle Like A Cyclone
Like Anderson, Bjorklund was a Swedish-American who moved from flyover country to New York and became an artist. In his case, he was born in Minnesota and began doing Western illustrations early, earning money during art school doing illustrations for pulp Western magazines.
Will James, Scorpion
In a reversal of the above artists, Will James was born to a city (Quebec) family, and left home to become a cowboy. Always an enthusiastic artist, he only focused on it after being bucked off a horse and seriously injured.
William Moyers, Broomtail
Moyers was from Georgia, but moved to Colorado as a teenager and ended up competing in rodeos. He went west for art school, to Los Angeles, and worked for Disney.