A simple understanding of the border picture style

Border-image:url: (images/whitebutton.png) 0 0 stretch stretch;
"0 12 0 12": In the clockwise direction is the width of the left border on the upper right, that is: 0; right: 12; bottom: 0; Left: 12.
Stretch | Repeat | Round is the method of image stretching after removing the bounding rectangle, the first stretch is the upper and lower Extrude method, the second stretch is the left and right stretching method:
Stretch: Specifies that the border background image is filled with a stretch.
Repeat: Specifies that the border background map is populated with tiling. When the picture touches the border, it is truncated if it is exceeded.
Round: Specifies that the border background map is populated with tiling. The picture dynamically adjusts the size of the picture according to the size of the border until it fills the entire border.

A simple understanding of the border picture style