下面是自己亲自做的
background-image:url('data:image/png;base64,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')

background:url('data:image/png;base64,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') right center no-repeat;

background-image:url(data:image/gif;base64,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%3D)

新写法，减少Http请求数，但是只有高版本浏览器才支持！

base64转码链接：http://imgbase64.duoshitong.com/ 

来自  https://www.cnblogs.com/yingsong/p/4736306.html

background url base64

这算是一种图片路径的新写法。将图片进行编码，然后存在文档中。
我先解释一下各自含义：
data: ----获取数据类型名称
image/gif; -----指数据类型名称
base64 -----指编码模式
AAAAA ------指编码以后的结果。

background-image: url(data:image/gif;base64,AAAA)这句话的意思总体就是“获取数据类型是image gif文件，编码采用ASCII 字符，ASCII编码内容是‘AAAA’”

我知道你清楚没。这实际就是一种新写法。原理和以往不同。
以往的图片路径写法是：
background-img:url(../image/xxx.gif)
图片需要加载服务器指定路径下的对应gif文件。
新写法就是：
background-image: url(data:image/gif;base64,AAAA)
图片本身就已经以ASCII的形式存在了文档中，只需要浏览器进行编译就可以了。

新写法将图片写入文档中，可以减少客户端对服务器的请求。
换句话讲，原来我们要加载图片，是从服务器下载。
现在浏览器直接把那一串ASCII按照你的文件类型进行编译就可以出来结果了。

来自  https://www.cnblogs.com/webglcn/archive/2012/09/29/2707986.html