You'll be hard pressed to find WW2 pics since they stopped wearing the kilt during Dunkirk. Googling Dunkirk and Camerons will give you some.

There are several good sites based on specific groups.
Camerons, the last to wear the kilt: http://www.eldonspecialties.com/df/camerons/
Liverpool Scottish, go to the trench exhibit: http://www.liverpoolscottish.org.uk/

This is a collection: http://www.gwpda.org/photos/greatwar.htm

Sort of my hobby, anything in particular you're looking for?

Art stores help the imagination but are not photos: