There are most popularly two types of 3D photographs: Anaglyph and Stereoscopic images. The methods to view both of these types of images is explained below for you to experience this fascinating technique comfortably.
Viewing Anaglyph Images
The following photograph is an Anaglyph image. You can see it in 3D with Red-Blue glasses.
This method is very easy to view the 3D image without any exercise but require you to wear 3D (Red-Blue) glasses. Just wear them and see the image in 3D!
If you don't have Red-Blue glasses, you can make them very easy. Just prepare some red cellophane and blue cellophane, and then place a piece of red cellophane over your left eye and a piece of blue cellophane over your right eye. Then, look at the anaglyph image to view the photograph in 3D (see the following figure)!
Viewing Stereoscopic Images
Following two photographs are one stereoscopic image that you can see in 3D with cross-eyed viewing method. The following steps will let you view the stereoscopic image easily.
Left Photograph Right Photograph
At first, keep more than 15 inch between the two photographs (or screen) and your eyes. When viewing a stereoscopic images, don't tilt your head, but keep horizontal level.
Look at the left side photograph with your right eye, and look at the right side photograph with your left eye. Since it is too difficult to do, here is an easy way: first, place one of your finger in the center of the two photographs and your eyes, and look at the top (or tip) of the finger (see the following figure).
You will see (or feel) a third image in center between the two photographs behind your finger. If you do not, then adjust your finger either moving it forward towards the photographs or backwards to your eyes until you see the third image in the center between the two.
Now fix your eyes on it (third center image) and carefully focus on the center image. When you are able to see it clearly, slowly remove your finger and enjoy viewing the 3D image!