Here are two background codes usually use in blogs. The difference is the first one, the image background moves when scrolled up and down. Of course this will make our eyes feel dizzy. And the second one is, the image background doesn't move when scrolled up or down. This is up to us which one is our choice.
First code :
background: #674ea7 url(http://image background) repeat scroll top center
Second code :
body {background: #000;background-image:url(http://image background);background-repeat:repeat;
background-attachment:fixed;
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