One, the dwellings on the right look like they're made of bark, not fabric. That might qualify them as wigwams, not tipis.
Two, I think we have to be leery of any photographic evidence. By the time photography came around in the late 19th century, tribes had been contaminated by a couple hundred years of European contact.
The best evidence would be drawings, paintings, or reports from an initial-contact situation. Anything after that becomes a record of a culture in transition.
Another factor is that this is exactly when the Plains Indians became well-known and popular. A tribe catering to visiting tourists might've adopted tipis to impress them. Or a tribe newly dependent on the government might've received tipis as an agency's idea of "Indian housing."
For some recent stereotypical uses of tipis, see Review of Apache vs. Gladiator, "Tardicaca Indians" in South Park, and Rapacious Cavalrymen in Family Guy.