@overholt If you don't know how stereograths work, they use parallax to produce a 3d image. You look at one image with each eye and your brain constructs a sensation of depth. Its pretty easy.
1) hold your phone sideways and open only the image, close any alt text or headers or footers.
2) hold the phone about 15cm/6in from your eyes, then cross your eyes so the two images merge in the middle.
3) move the phone slightly in and out until the image is in focus.
That's it. Might take practice.
@SkipHuffman 3D doesnβt work for me, unfortunately, because of my amblyopia, but one of my favorite projects from the sadly defunct NYPL Labs was the Stereogranimator, which you could use to turn them into GIFs. https://stereo.nypl.org