Video narration
Here’s a simple way to see what a convex lens does to light rays from different points. A convex lens is thicker in the middle, and it bends light inward. Imagine one point on an object sending out rays in many directions. Draw a few of those rays heading toward the lens. As each ray passes through, it changes direction, and the rays from that same point start moving toward one another. If they meet, they form an image point on the other side. Now pick a different point on the object, above or below the first. Draw its rays too. They bend in the same “toward the center” way, but they head to a different place after the lens, making a second image point. Put those image points together, and you get the full image: many points in, many points out. That’s the basic idea— a convex lens redirects rays so they converge and map each point to a corresponding point.