You create the image of an object a creature or some other visible phenomenon that is no larger than a 20-foot cube. The image appears at a spot that you can see within range and lasts for the duration.
As long as you are within range of the illusion you can use your action to cause the image to move to any other spot within range.
A spellcaster casts major image. Can they move the illusion created by major image out of their sight? Does the answer change depending on whether "out of sight" means "behind total cover" or "heavily obscured but not behind total cover"?
following the principle that spells only do what they say they do.
The only stipulation the spell description gives is that the area you move the image to be in range. If there was a restriction that the caster can only move the image to a visible area it would be stated be specifically.
In fact, it specifically states you can move it to "any other spot within range."