This is a black and white photograph. In the picture, two people are operating a large computer system. One man stands in front of a console from which a printer is operating. A woman stands in the left background of the image and appears to be operating a console. The picture is captioned with "LEO MARK I" and "An illustration of Leo Mark I installed at J. Lyons & Co. Ltd., Cadby Hall, and working regularly since January 1954." On the verso, "PPT Thys" in black ink. Also "JAN" is written in red ink.