You may have seen this site before, but if not, thought I past the link. As part of Time Warner: Picturegoer, Picture Show, Film Weekly and Film Pictorial magazines has been online for a few years with images of their magazines covers. This is a commercial site with covers being sold as posters. They also have a section where you can search for original copies of these magazines. They do have a collection of Charlie Chaplin images to browse, plus many more from the classic film era. If you have not seen this site, here are a few links to check out.
Home page link to Picturegoer: (this page has links to the three other magazines mentioned)
Film Pictorial link on Chaplin: