I've seen a few tricks on how you resize an image you want to use inside an IMG-tag but I want to have an image variable inside a Javascript, resize it and then use the image inside a context.createPattern(image, "repeat"). I have not found any hint on how to do that. You can find a functional demo at http://karllarsson.batcave.net/moon.html with images on what I want to do. The solution from Lokt