A 360 degree photo, or "360 panorama" is a panorama that images a full 360 degrees around a circle. Snapspheres require a special type of 360 degree photo (sometimes called "360x180") that captures a full 180 degrees up-to-down in addition to 360 degrees around. For this reason, 360x180 images are twice as wide as they are tall.
360 degree images can be taken with a special 360 degree (or "omnidirectional") camera. Some apps are also capable of creating 360 degree images, by taking multiple regular images and stitching them together. But these apps sometimes leave conspicuous stitching artifacts in the images they create.