The portal 1418: documenti e immagini della Grande Guerra has been launched in 2007 by five Italian cultural heritage institutions in Rome to present digital collections of various materials concerning the First World War. One of the sections presents digitized journals (periodici) from several European countries. Photographs, manuscripts, drawings, maps, posters and pamphlets are also present. The first album in the Cimeli section contains numerous cartoons.The interface is only in Italian.
The page Risorse in rete (Sources on the web) offers you a repertory of websites concerning the First World War in Italy and elsewheren.