Unable to see inside object I'm using an image as texture for sky background on a sphere, however I'm unable to see inside of that sphere, which is the whole point of background image.
Thanks.
Select everything, click CTRL+N and then flip normals

Normals is the vector value that represents face's direction. By default normals are directed outside of the sphere, so everything will be displayed correctly only on this side. When you flip normals, you flip the direction of the faces to make them facing inwards.

Also, if you want to use this sky as background or lightning, make sure to check out what HDRI is and how to use it in blender.