It's a little difficult to be sure what this object is. My best guess is it's a photograph which has been augmented by an artist to provide better detail.
We know the location is Camp Chenowith in the Dalles, on July 1, 1891, and the notes on the reverse link it to the Blowers family of Hood River. The notes say:
Encampment of the Third Regt Infantry Oregon National Guard at Camp Chenowith, The Dalles, Oregon, from June 28th to July 4th inclusive. Nine companies present aggregating about 450 men. Col. T. A. Houghton in command. Company "D" Captain A.S. Blowers in command won challenge (silver) cup in competition drill. Following is a list of Field Officers of the Regiment: Colonel T. A. Houghton. Lieut. Col. G. T. Thompson. Major Jay P. Lucas. Adjutant Lieut. J. F. Haworth.// L. N. Blowers, 2nd Lieut. Co "D".
Where was this encampment? It appears to line up pretty well with the Home Depot parking lot!