There are a few photos on the Scottish Military Historical Society's web site:

http://www.btinternet.com/~james.mckay/dispatch.htm

About half-way down the page, you'll see a link (No. 5) for "Scottish Military Illustrations. There is a section for 20th century photos.

It's not on the web, but the best printed source for this query is the Osprey book, "Scottish Divisions of the World Wars" by Mike Chappell:

http://www.ospreypublishing.com/titl...=P4695&ser=ELI

Besides the full-colour prints, it is full of pictures from the First World War.

Cheers,

Todd