Okay kiddo, think of an image like a drawing or a picture that you took with a camera. Editing an image means changing things about it like adding drawings, making it brighter or darker, or changing the colors.
It's like when you play with your coloring book - you can use different colors to make your picture look different.
When you edit an image on a computer, you can use special programs like Photoshop or Gimp. These programs let you use different tools to change things in the image like making it brighter or darker, or making parts of the picture disappear.
Think of it like playing with your toys - you can use different ones to make your picture look just the way you want it to.