What a great photograph. I'm thinking that at that time people were still transitioning from horse-drawn transportation to automobiles. And yet the mechanics had probably long forgotten horses and were experts at what they did. I wonder if the building where this was photographed still stands.
No, the building is long gone. The garage was moved to a different location by the 1940's. Robert Smith, my great-grandfather was a mechanic in a garage as early as 1920 as this was listed as his occupation in the 1920 Jefferson County, IL census.