Question

I wonder 'image is formed by intersection of 2 light rays' . Can't it be a single light ray to form an image ? Some sources do suggest that a single photon can form image

What's the relationship between light ray and a photon? & If image can be formed by single photon how to our eyes know from how far that came?

Answer 1

A single light ray can and does indeed form an image.

Explanation:

A single light ray carries the information of a single point of an object. Moreover it has very little intensity. So although a single ray will form an image, it will be very dark and out of focus.
Because of this reason, we use lenses to merge many such rays at one point. This increases both the intensity and sharpness of the image.

From the image we can see that the point at which the rays merge acts like the original object and the rays seem to be emerging from there instead.