Thanks much, Flole, that works. The GET request did not seem logical for a command to change a state.
Changing POST to GET like the following works great.
Switch GarageCamOutput { http=">[ON:GET:http://192.168.1.104:8080/0/config/set?output_pictures=on] >[OFF:GET:http://192.168.1.104:8080/0/config/set?output_pictures=off]" }