Sometimes I post a 3D image using the anaglyph technique. That is a method where colors are used to separate the left eye image from the right eye image on the screen. In order to view the 3D image you must wear a pair of special glasses with colored lenses.
There are several systems for using color separation to obtain the 3D effect. I use the red/cyan system since that appears to be the most common now. Here is a photo of the 3D Anaglyph glasses that I use for viewing my own images.
As you can see in the photo, the lens that goes over the left eye is red and the lens that goes over the right eye is cyan. So the left eye sees everything in the image except for items that are red, which are filtered out by the red lens, and the right eye sees only the items in the photo which are red because the other colors are filtered out by the cyan lens. Your brain mixes the two images together into a stereo image. No extra charge for the headache you can get while your brain does this work.
Anaglyph images seem to be dark when viewed through the glasses because a lot of the light is filtered out. Because of that I have slightly over exposed the image shown here. They also seem to vibrate because neither eye sees all of the colors and that is visually confusing. Since the filters are not perfect, you also get some ghosting because the red filter does not filter out all of the red and likewise for the cyan filter. You can see the ghosting in the anaglyph image below if you have glasses. I have found that I can view the anaglyph 3D images better if I put on the glasses and give my brain a couple of minutes to settle down. I takes a while to get used to the weird color sensations.
That said, using anaglyph images allows you to see 3D images without having to learn any tricks with your eyeballs. You just put on the glasses and look. Now that I can see the full color 3D images using just my eye techniques, I would suggest that you try to learn my parallel-eye technique or my crossed-eye technique because the images are much better in full color.
If you already have a pair of glasses like the ones in the photo above, you can see the following image in 3D.
The glasses are Anachrome glasses produced by the fellow who runs the web site www.anachrome.com . They purport to have a subtle diopter correction in the red lens to correct for the difference in focal distance between the cyan color and the red color, and that allows you to see the images with less eyestrain. You can read the details out at the web site.
I bought my glasses from a different web site called www.berezin.com. I have no business relationship with either of these two companies other than having purchased the glasses.