The link above will show you how to link photos and add photos to a corner gallery. There are size limitations but that is easy enough to workaround. All you need to do is open your image in something like lightroom, photoshop etc and scale your image to about 1280 pixels on its longest edge. Even at 300dpi I have not had a scaled image be too large.
Alternately you could subscribe to a service like photobucket, smugmug or other gallery hosting service and then link to the files from there as well.