Specify the size of a background image:
The background-size property is supported in IE9+, Firefox 4+, Opera, Chrome, and Safari 5+.
The background-size property specifies the size of the background images.
|length||Sets the height and width of the background image. The first value sets the width, the second value sets the height. If only one value is given, the second is set to "auto"||Play it »|
|percentage||Sets the height and width of the background image in percent of the parent element. The first value sets the width, the second value sets the height. If only one value is given, the second is set to "auto"||Play it »|
|cover||Scale the background image to be as large as possible so that the background area is completely covered by the background image. Some parts of the background image may not be in view within the background positioning area||Play it »|
|contain||Scale the image to the largest size such that both its width and its height can fit inside the content area||Play it »|
Stretch the background image to completely cover the content area.
the background-image to four copies horizontally
Stretch the background image so that exactly four copies fit horizontally.
CSS3 tutorial: CSS3 Backgrounds
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