Lance Robertson posted a postcard from the Willows - I believe it is the one that was run by Graham and McKay in the 1931-1932 time frame. The image is a little small but take a look at the guy behind the roulette wheel - looks sort of like the guy on the right in your postcard. Interesting....

Here is a link to Lance's post:

http://www.thechipboard.com/cgi-bin/tcb/tcb.pl?read=537842