This image shows two pre-Civil war homes built in the style of the steamboats of the era, and thus the term Steamboat Gothic Architecture.

Color Photo by Joe E. Clark
The description states:
Two Pre-Civil War Homes in historic Galena in northwestern Illinois. Here are splendid examples of the “steam-boat architecture”.
–The gothic nature of the design is evident in the tall, narrow, round top window shapes. This image likely dates from the 1950s.