http://www.w3.org/TR/css3-background/#the-background-size

[#d01]
[#d02]
[#d03]
[#d04]
[#d05]
[#d06]
[#d07]
[#d08]
[#d09]
[#d10]
[#d11]
[#d12]
[#d13]
[#d14]
[#d15]
[#d16]