多张图片合成一张，显示时只显示一张，只显示图片中的一部分

.foot_p_2 .foot_pic_a{width:35px; height:43px; display:inline-blcok;margin:0 10px 0 30px; float:left;background:url(../../common/img/icon/footer_ruanko_logo.png) no-repeat -97px -15px;}
.foot_p_2 .foot_pic_b{width:35px; height:43px; display:inline-blcok;margin-right:10px; float:left;background:url(../../common/img/icon/footer_ruanko_logo.png) no-repeat -133px -15px;}
.foot_p_2 .foot_pic_c{width:35px; height:43px; display:inline-blcok;margin-right:10px; float:left;background:url(../../common/img/icon/footer_ruanko_logo.png) no-repeat -61px -15px;}