One creative activity for teaching binary image representation to 15 year olds could be to have them create their own pixel art using a grid and binary code.

First, provide the students with a blank grid (such as a 10x10 or 20x20 square) and explain that each square on the grid represents a pixel.

Next, introduce the concept of binary code and how it can be used to represent colors in an image. For example, 00000000 could represent black, while 11111111 could represent white.

Then, have the students choose a simple image or design to recreate on their grid using binary code. They can use a chart or reference sheet to help them convert each pixel to binary code.

Once they have completed their pixel art, have them share their creations with the class and explain how they used binary code to represent the colors in their image. This activity not only reinforces the concept of binary code, but also allows for creativity and artistic expression.