From the Canadian War Poster Collection, McGill University Library Digital Collections website:

The holdings of the Print Collection in the Rare Books and Special Collections Division include some 250 Canadian posters from the two World Wars. The posters are accessible to researchers who visit the Division's Lande Reading Room; a printed finding aid is available from the Reading Room Supervisor.

This website contains basic descriptions and images of each poster, an artist index, and an essay about Canadian War Posters.