What Does a Computer See?

Explore the actual numbers stored inside a digital image. Upload a picture or take a photo, then inspect the RGB values of its pixels.

The key idea: A computer does not receive a picture in the same way that you do. It receives numerical values arranged on a spatial grid. In a color image, each pixel normally contains three values: Red, Green, and Blue (RGB).

1. Choose an image

Upload an imageTake a photo

No image selected yet.

2. The image

Choose an image above to begin.

Click anywhere on the image to inspect that pixel. The selected pixel is marked in the image.

3. Selected pixel

X coordinate—

Y coordinate—

Red—

Green—

Blue—

Array index—

RGB = (—, —, —)

4. First 50 pixels

These are the first 50 pixels in the image array, starting at the top-left corner. Each pixel contains four values in the browser's RGBA array.

#	(x,y)	R	G	B	A

5. A small neighbourhood

The pixels around a selected pixel are not just random numbers. Their values are arranged according to their positions in the image. This local organization is part of the image's spatial structure.

Think about this:

The computer receives numbers, but those numbers have locations. If we rearranged the same numbers into different positions, we would create a different image.

The numbers matter — but their spatial arrangement matters too.