Likely use of the background tag's options:
background: url('http://www.yoursite.tld/image.type') #666666;
background-repeat: no-repeat;
background-position: center;

http://www.w3schools.com/css/pr_background.asp
http://www.w3schools.com/css/pr_background-repeat.asp
http://www.w3schools.com/css/pr_background-position.asp

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