The code starts by fetching a random dog image URL from an API. It does this using the Fetch API, which is a modern method for making network requests in JavaScript.
The code also loads the same image in another canvas element (canvas2) and then applies a grayscale filter to it. It does so by taking the RGB values of each pixel, converting them to grayscale using a weighted average formula (where red, green, and blue channels are combined with specific weights), and replacing the original color.
To trigger the grayscale conversion, the code adds a click event listener to the canvas2. When you click on the grayscale image, it gets converted to grayscale.