i have no doubt the picture is real, but
i do think it was staged.
there is no way those two horses pulled that load, just think about it
if the logs were shaped with a leading edge, and the load was on a frozen lake
of smooth ice, and the horses could get some traction,, maybe, but even then unlikely.
pulling a load is only part of the job, controlling the load is another. those two horses could not pull or control even a quarter of that load under the best of circumstances.
this is just one of many staged photographs taken back in the day.
remember the pictures of grasshoppers with saddles and the jackalope?
there is easily over a quarter million pounds of logs in that stack!
bob g