Background() code for image object

HI! We are all familiar with the background code to clear off our canvas to continue rendering other stuff. But we dont have a “background()” code for our image. I could use this function
```js
for (let i in img.pixels) {
img.pixels[i] = 255;
}
```
But it is not very efficient in performance. I wondered if there is another way I could achieve this without losing too much performance?