These pages have images that may or not be sourced. If they do have sources, it's not clear if OW can legally use them. If you know the owner of the image, it would be awesome to contact them and see if we can use the images and then mark appropriately.
Even better, it would be great to take your picture and replace the existing image with one that can be used under a creative commons license. For more information about copyright, check here.
Some good places to check for already existing images online under creative commons are Flickr, either by searching for pictures tagged as usable under CC or using their commons database, and Wikimedia Commons. You can also do a google image search and edit the search for pictures tagged for reuse.
Many historical images are available at the Oakland History Room. The librarians there are very helpful and can help you find whatever you're looking for. If you use an image from the OHR, they've asked that you caption it ""Courtesy Oakland History Room, Oakland Public Library." This is a great resource!