I've always felt the better western artist and especially the ones from the period are somewhat akin to the painting equivalent of a Ken Burns film. By telling a story with little more than what's in front of you and a interest in telling that story. In a lot of cases, the only records of events we have, are these paintings.
In the case of this painting..it does just that..it's telling us a story and puts us right in the 'wash so to speak