camera basics - How does a circular lens produce rectangular shots?

Is it something like the sensor captures a circular image and then what we get is the cropped version?

Something like this:

Or did I get it completely wrong?

Answer

You are correct.

Photos are the size and shape they are just because of the size and shape of the film or digital sensor used to capture the image from the lens. The rest of the image that falls to the top, bottom, and sides of the film or sensor are just not recorded.