What is a 360 equirectangular image, in plain words?
A 360 equirectangular image is one flat rectangle that holds a full sphere of view — everything above, below, and around the camera. When you load it into a VR headset or a web viewer, you can look in any direction and the image wraps around you. The shape is always 2:1 (twice as wide as it is tall), which is the standard every panorama viewer expects.

