The association of the two photographers, Smith and Hooper, in Washington, KS, must have been a very short one. No photographer Smith has been found in a page by page search of the 1900 US census in Washington, KS, or page by page search of the 1895 and 1905 Kansas state census.
Henry Thomas Hooper, photographer, his wife Florence Adeline and brother in law, Howard A West were found in the 1900 US census living at 46 First st in Washington, KS. Henry and his wife were living in Cuyahoga County, OH, at the time of their marriage in 1893. Their next appearance after the 1900 US census is the 1910 US census placing them back in Cuyahoga County, OH.
A genealogical accounting of the Hopper family mentions that Henry was a Washington, KS, city councilman for three years. (see below)
So Henry Hooper could have been in Washington, KS, any time between 1895 and 1905 for at least three years. The partnership with Smith would have to be during that time also.