If you like old photos of Bangkok you might be interested in the current gallery at the Bangkok Culture Center. (the BCC is directly across from MBK)
The photographs are mostly from around 1920's to the 1960's, but there were a few from the late 1800's.
I really love looking at old photographs and wanted to pass this on. It was really funny to see the streets of Bangkok with no traffic.

Translated from the
BCC page"Old story".
Date: 12 July -12 August 2554.
Location: curved walls, floors 3,4 and 5.
Publisher: Bureau of Culture, Sports and Tourism. Bangkok
Exhibition of old stories. Incident at Bangkok's broadcast on over 100 years, 150 photo images to see the beauty in the past. And changes of Bangkok. Presented in terms of aesthetics. Combined with cultural and historical dimensions shown in the picture.