Before you do any gluing, load your images onto your digital picture frames and test them out. They should come with a manual to tell you how to do this. Also set the slideshow time to the fastest setting to make it more "video"-like. These particular models only have options for 5 seconds, 10 seconds, or 30 seconds.
While you are at it, charge up the devices (mine came with a USB cord for loading/charging). I had to find a Windows machine because the brand I had was not compatible with Macs.
Because the picture frames I used were thinner on one side, I installed one upside down so they would mirror each other (see picture). I had to upload the images for that frame upside down so they would display correctly. You can flip them in any image-editing software before loading.
Using a hot-glue gun, attach the digital picture frames to your glasses. I worked my way around the frames a few times, layering up the glue to make a sturdy connection.
Be sure to leave room between the frames to plug them in if needed (as you can see from the pictures the USB connection is right across the bridge of the glasses; that's not a lot of space to work with).
If you want, use some paint to cover the hot glue and make the digital frames blend in with your glasses.
And that's it. Try them out and impress your friends! These were a big hit at a Halloween party and I've heard of a few people using the technique to make other interesting costumes.