This photo shows part of the 1909 World's Fair held in Seattle, the Alaska Yukon Pacific Exposition. It was licensed from Frank Nowell, the official photographer of the exposition, and apparently printed on contract for the American Post Card Co.
The signature has not one but two typographical errors - "American" is misspelled as "Americam" and "Post" is misspelled as "Poast."
There is also an Image 21 (21 - Cathedral Seattle) showing the dedication of the St. James Cathedral in 1907.