HORSE ART IS A FORM OF ANIMAL WORSHIP, AND no real equestrian can resist it -- a fact that must, for instance, at least partly explain Paul Mellon's fondness for George Stubbs, the 18th-century British sporting painter. The National Gallery of Art benefactor does, after all, raise thoroughbreds on his 4,000-acre Rokeby Farms near Upperville.

True equestrians prize their animals almost as much as their own flesh and blood. Just ask Kathleen Beer, whose Beresford Gallery in Potomac is in the business of immortalizing horses -- and sometimes lesser animals too -- for their owners. Since she opened Beresford in 1969, the business has expanded to West Palm Beach, Fla., and Saratoga, N.Y. Beer follows the circuit (steeplechase, thoroughbred racing, polo), rotating her business among galleries as the season dictates. Now it's polo season in Washington, and local commissions are pouring in, she says. Portraits are the gallery's profit core, and the horse -- even at as much as 30 grand per canvas -- is a more popular subject than the rider.

Beresford's headquarters, situated deep in the woods of Beer's Potomac estate, looks remarkably like a stable -- particularly when her 14-horse trailer is parked in front or her string of polo ponies parades by en route to the daily workout. Inside the gallery are horse portraits-in-progress, paintings and sculptures of every equestrian sport invented in the last three centuries, and sometimes even a live miniature horse or two.

Living "the life" is essential to working in this field of art, says Beer, a former steeplechase competitor who still paints horses herself. Everyone in her family plays polo and fox hunts, including husband Robert, when he can get away from the downtown mortgage investment firm Ivor B. Clark.

"Sporting people are literal," Beer says. "You have to really understand the sport to depict it. The most exciting polo sculpture in the world won't sell if it's technically incorrect." Accordingly, all the artists she represents are equestrians. One raises polo ponies on a Wyoming ranch, another judges and paints dressage in Vermont. Canadian Pamela Edwards fox hunts and paints -- you guessed it -- hunting scenes.

"Pam's done the queen four times," Beer says casually. Beer has "done" a few royals herself. The Beers and the Windsors are polo buddies, and Sarah Ferguson was a house guest after a pre-Andrew backpacking trip. "She had a broken leg and wore dirty jeans," Beer recalls.