Scaling background image to size of browser
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Hi I'm trying to achieve what this website does with their big black and white image: http://oldbarbershop.com.au/

As you resize the browser window from the corner, the image resizes so that the whole picture fills the whole frame proportionally. Does this require a specific jquery plugin? or CSS3? I've seen many solutions such as setting the image background-size: 100%, but those don't exactly 'resize', rather just fill the whole frame. 

Thanks for the help!