Prepare the HTML Structure: Begin with a basic HTML setup, including an image and a canvas element. Load the image onto a canvas. Retrieve the image data. Apply the grayscale formula to each pixel. Update the image data with the new grayscale values. Sample Code Here's how the complete code looks: img.onload = function () {

Recently, I was inspired by Jeremy Howard's insightful video on CUDA, where he introduces the concept of converting a color image to grayscale. This sparked an idea: why not try this in JavaScript? The Core Concept The heart of this process lies in a simple formula used to transform a color image into grayscale: [ Y = 0.2126R + 0.7152G + 0.0722B ]

HTML: JavaScript: We can use the CSS property filter to make an HTML element display in grayscale: It can make any HTML element in grayscale but if we need to save the image in grayscale, we cannot use this approach. HTML5 provides a canvas element which provides a way to manipulate image data.

Grayscale.js allows you to easily send images to a separate javascript thread that will quickly convert them to graysclae and send them back. This way you only send one of each image to the client, the browser processes them once and won't have to paint them on the fly, and the resulting image is stored in their cache to speed up future pageloads.