Specify the size of a background image:
The backgroundSize property sets or returns the size of the background images.
The backgroundSize property is supported in IE9+, Firefox, Opera, Chrome, and Safari.
Return the backgroundSize property:
Set the backgroundSize property:
|auto||Default value. The background-image contains its width and height|
|length||Sets the width and height 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"|
|percentage||Sets the width and height 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"|
|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|
|contain||Scale the image to the largest size such that both its width and its height can fit inside the content area|
|initial||Sets this property to its default value. Read about initial|
|inherit||Inherits this property from its parent element. Read about inherit|
|Return Value:||A String, representing the background-size property of an element|
CSS reference: background-size property