.pics_1{
    background-image: url(../img/posts/post1.jpg) ;
   }
   .pics_2{
    background-image: url(../img/posts/post2.jpg) ;
   }
   .pics_3{
    background-image: url(../img/posts/post1.jpg) ;
   }
   .pics_4{
    background-image: url(../img/posts/post2.jpg) ;
   }
   .pics_5{
    background-image: url(../img/posts/post1.jpg) ;
   }
   .pics_6{
    background-image: url(../img/posts/post1.jpg) ;
   }
   .pics_7{
    background-image: url(../img/posts/post2.jpg) ;
   }
   .pics_8{
    background-image: url(../img/posts/post2.jpg) ;
   }
   .pics_9{
    background-image: url(../img/posts/post1.jpg) ;
   }
   .pics_10{
    background-image: url(../img/posts/post1.jpg) ;
   }
   .pics_11{
    background-image: url(../img/posts/post2.jpg) ;
   }
   .pics_12{
    background-image: url(../img/posts/post1.jpg) ;
   }