This image shows a horse drawn field artillery piece, being led by a mounted rider, on parade in Fort Bliss, Texas.
Colorpicutre Publication, Cambridge, Mass
The description states:
One of the crack artillery regiments of the U. S. Army, the 82 Field Artillery is located at Fort Bliss, just outside El Paso, Texas.
The 82nd Field Artillery Regiment was named in November of 1917 and assigned to Fort Bliss. Its previous name was the 24th Cavalry. It changed names again in 1921 to 82nd Field Artillery (Horse) Battalion, and was the only horse artillery unit in the Army at that time.
Thus this image likely dates to the 1910s.