Note that the dog on the right is tethered by a tow line (longer) and the other dog gets a short neck line tether. It may be that the dogs in the previous post were less cranky because the straw focused their attention on rest rather than competing for a spot on hard-packed snow.
The caption on the reverse side suggests another scenario: "What do you mean, I didn't pull." While that's possible, usually a dog that is upset with another will not wait for the checkpoint to settle the score.
This postcard, dated 1994, was published by Leader Publications of Fairbanks, Alaska. An internet search did not turn up a Web site. The photographer is Vladimir Vinitzki. See another Vinitzki phototgraph at Picture.com.