There is actually an easy trick to seeing them in 3D without a viewer. Not everyone can do it, but all you have to do, is look at the images, and cross your eyes slowly until they create a third image in the middle. If you keep your eyes crossed just at the point where the two images merge into one in the middle, and keep looking at the center image, your brain will do the rest. The image will suddenly come into focus in 3D.
Cool images when they come into focus in 3D, but my only issue is the images seem too small. When they come into focus in 3D, the center image is too closely bordered by the other two, and my eye has a hard time maintaining focus on just the center image. I think horizontal crops tend to work better for these types of images.