You can change the information contained in a photo manually. In windows, do a right-click on the picture and then in properties go to the details tab. enter whatever seo relevant data applies e.g. title, subject, comments, author and coypright info, camera specific data. Don't know if SEs can retrieve this kind of data, but it might be worth a try.
Added: seems this is only possible to jpg and tiff files. couldn't find a way to add this to gif or png files.