1952 Stereo Realist (built 1947-71)
Stereo camera - David White company
You can see stereo pairs by relaxing your eyes about 18" (45 cm) away from the screen (some people say go cross-eyed). It takes some practice but you will see multiple images and can move the two center images together to make a single, 3d image. Try looking at different sizes and see what works best and try moving further back. Picking out some distinct feature to "merge" in your minds-eye helps.

Several web browsers let you zoom your browser in and out with CTRL-mouse wheel which changes photo sizes and that might help.