How do you create image's color picker app?

How to create image's color picker app.
Can you give an extension.

What do you mean? Do you want to return all the colours in an image, or a single colour from a particular position in the image?

Single color from a particular place

Do you mean get the color code or HEX from an uploaded image?

Set the image to a canvas background, then a touch can return the pixel colour, alternatively enter x/y coordinates to return the pixel colour.