Newspapers can be good sources for photographs, editorials with images, advertisements, cartoons, and other images. If you're looking for a specific newspaper, use the Journal Locator to search it by title, and see what database it's in and for which years we have access.
These databases have collections of newspapers published generally pre-1990, often digitized from print or microfilm. They are searchable, but be aware that the results won't be as accurate as born-digital newspapers.