displa:inline-block出现空白bug

** .js文件 ** var dataStr =data[i].memberName+','+data[i].sex+','
+data[i].major;

                    var str = '<div class="t1">'
                    +'<img style="width:150px;height:200px;" src="/upload/member/'+data[i].memberImage+'" /><p>'
                    +dataStr+'</p></div>';
                    $("#大二").prepend(str);

**.ftl文件 **      <div id="2013" class="picture">
        <div class="level_1">
 <span>2013级</span____>

.css文件
.t1{
margin-top:20px;
margin-left:40px;
width:200px;
text-align:center;
float:left;
}