I have an image that is 1024×1024 and is divided into 4 quadrants:

I would like to shrink this image down such that quadrant 2 is 256×256 and mask out, or hide, the other 3 quadrants such that it is only visible on the page. Like this:

How can this be done? Is it possible with pure CSS or is js needed along the way?
Assuming the browsers you’re targetting (FF4+, IE9+, Safari 4.1+ Chrome 3+) can use the
background-sizeCSS property, then you can do this in CSS alone:If you remove the red keyline between each section then the size property can be made
512pxand it would make the calculation easier, should you need to resize again in future.Example fiddle
More information on background-size