In the “Golden Age of Postcards”, roughly 1905-1925, most postcard illustrators worked anonymously.

https://en.wikipedia.org/wiki/Postcard

A few (who were especially popular, skilled, prolific, or had the means to support themselves independently) sold their signed works to one of the many postcard publishing companies as contractors.

Lewis H. Larsen, who adopted the moniker, “Dude”, began his artistic career in the 1930’s as a hard-headed business person who copyrighted his own illustrations and generated his own publicity.

(His business practices in areas not related to his artwork, led him into legal squabbles in three states.)

Riding a wave of nostalgia for the vanishing life of the cowboy (the long cattle drives had ended soon after the railroads connected all the towns of the western US), Larsen created a library of cowboy-themed illustrations.

“Dude” Larsen managed his own printing, copyrighting, publishing, and distribution, so that he was the sole beneficiary of his creative endeavors.

His strategy was successful, and he retired to a comfortable life in Kane County – on the Arizona border of southern Utah.

https://postcardhistory.net/2019/10/lewis-h-dude-larsen/

This postcard illustration was copyrighted in 1939.

A cowboy and his horse are sharing a drink directly from a mountain stream.

The lush landscape is devoid of any other person – part of the cowboy mystique was rugged individualism.

On the reverse, a primitive verse (also by Larsen, it is thought) argues for the superiority of the mountain stream above any other refreshment.

The title, “A Drink of Water”, is usually applied to the picture and the verse.

The postcard was not mailed; it may have been one of the many Larsen illustrations collected by his fans.