Way 1: Light from things enters your eye. It goes past the colored part (the iris) and through the lens. The back of the eye (the retina) gets the picture upside down. Tiny wires (nerves) send that picture to your brain, and your brain turns it the right way up so you can see.
Way 2 (step-by-step):
1) Light bounces from a toy or tree into your eye.
2) It travels through the iris (the colored circle) and the lens (a clear part that focuses).
3) The retina at the back catches the picture, but it looks upside down there.
4) Nerves carry the upside-down picture to your brain, and the brain flips it so it looks normal.
Way 3 (camera idea): Your eye is like a camera. Light goes in and the lens makes a picture on the back of the camera (the retina). That picture is upside down, so the brain is like the camera helper who turns the picture the right way before you see it.
Way 4 (little story): Imagine tiny light helpers run into your eye and draw a picture on the back wall (the retina), but they draw it upside down. Then the brain reads the drawing and flips it over so you know what you are looking at.