Css Sprite

.rtf{background:url(../Images/css/allbgs.png) no-repeat 0px 0px;width:13px;padding-top:18px;}
.txt{background:url(../Images/css/allbgs.png) no-repeat -13px 0px;width:13px;padding-top:18px;}
.word{background:url(../Images/css/allbgs.png) no-repeat -26px 0px;width:16px;padding-top:18px;}
.excel{background:url(../Images/css/allbgs.png) no-repeat -42px 0px;width:16px;padding-top:18px;}
.pdf{background:url(../Images/css/allbgs.png) no-repeat -58px 0px;width:16px;padding-top:18px;}
.ppt{background:url(../Images/css/allbgs.png) no-repeat -74px 0px;width:16px;padding-top:18px;}
                            
[解决办法]
直接用background:url(allbgs.png)就行，路径是相对于css文件的