Rollin M. Foster (14 Feb 1858 - 26 Feb 1924)
All documents list him as a photographer beginning with the 1900 US Census.] but he was probably already established by 1880.
Documents show R. M. Foster was in Kansas from 1886 to 1897 then to Iowa for a couple years.
The US Census for 1900 says he was back in Kansas.
Then the 1910 US Census says he is back in Iowa at 52
The cabinet card at the left was probably finished between 1886 and 1897.
A comment from Flickr viewer Claire :
Mr. Foster really got around. He had studios in Pleasantville and Harvey, Iowa as well as in Missouri before coming to Cawker City. He married Miss Ayres in Cawker before they moved to Enterprise where she died. R. M. Foster was not his real name. He was trying to hide his Jewish heritage. Later, he moved to Lincoln, Nebraska where he took the name of the street he lived on!.
Cawker City KS
From the collection of KEN on Flickr
photographer: R M Foster
Cawker City, KS
from Flickr member Clair
Is this the same Foster that worked in Cawker City, Kansas? Lamar, MO, is about 260 miles from Cawker City, KS.
More research pending