This print of some cowboys and horses taking a break in the shade, appeared in a 1975 “Artists of the West” calendar by Western Horseman Magazine.

Sizes I have found:
6 1/2 x 8 1/4 inches

From a 1967 painting titled: “Shaded Up”
Oil on canvas, 16 x 20 inches

The original painting was offered at Sotheby‘s New York Auction, December 1, 1994, titled “Papago Rancho.”