HTML Background image should auto tile smarter

When designing the background for this blog page, an idea came to mind, wouldn't it be nice if you could provide a single image, and have HTML/CSS automatically tile, so that it flips the image down and across keeping the pattern intact. In this case the spider web, now forms an expanding and shrinking web, as you scroll down, the catch is that I had to modify/upload the image which ended up twice as big, so it could then use the normal HTML tile to continue the vertical pattern.