Pages at Cryptogams in Depth
include stereo
images in parallel JPG format,
with the left image to the left and the right image to the right.
The test image above (the slime mold, Trichia sp.,
"fruiting" on the lichen, Lobaria
oregana.) is shown in slightly smaller format than the
others at this site, to make practice viewing slightly easier.
To view the image in stereo, let your
eyes relax and go "wall-eyed" (opposite from cross-eyed, letting the
eyes move outwards from their normal point of focus). As you
do this, you will see three images forming. When the third,
middle, image is the same size as the left and right, it will consist
of the overlain two images and will appear in stereo.