使用CSS在背景图像上设置大小？

是否可以使用CSS设置背景图像的大小？

我想做的事情如下:

background: url('bg.gif') top repeat-y;
background-size: 490px;

但似乎这样做是完全错误的......

如果需要使图像更大,则必须在图像编辑器中编辑图像本身.

如果您使用img标签,您可以更改大小,但如果您需要将图像作为其他内容的背景(并且它不会像您似乎想要的那样重复),那么这将无法获得所需的结果...

这可以在CSS3中使用background-size.

所有现代浏览器都支持此功能,因此除非您需要支持旧浏览器,否则这是实现此目的的方法.
_{支持的浏览器:}
^{Mozilla Firefox 4.0+(Gecko 2.0+),Microsoft Internet Explorer 9.0 +,Opera 10.0 +,Safari 4.1+(webkit 532)和Chrome 3.0+.}

.stretch{
/* Will stretch to specified width/height */
  background-size: 200px 150px;
}
.stretch-content{
/* Will stretch to width/height of element */
  background-size: 100% 100%;
}

.resize-width{
/* width: 150px, height: auto to retain aspect ratio */
  background-size: 150px Auto;
}
.resize-height{
/* height: 150px, width: auto to retain aspect ratio */
  background-size: Auto 150px;
}
.resize-fill-and-clip{ 
  /* Resize to fill and retain aspect ratio.
     Will cause clipping if aspect ratio of box is different from image. */ 
  background-size: cover;
}
.resize-best-fit{
/* Resize to best fit and retain aspect ratio.
   Will cause gap if aspect ratio of box is different from image. */ 
  background-size: contain;
}

.resize-best-fit-in-repeat{
/* Resize to best fit in a whole number of times in x-direction */ 
  background-size: round auto; /* Height: auto is to keep aspect ratio */
  background-repeat: repeat;
}

background-size: 200px 50px;

background-repeat: no-repeat;

background-position: center top;

background-position: 20px -14px;

background-size: contain;