.zoom_img img{

height:auto;
width:15%;
-moz-transition:-moz-transform 0.1s ease-in; 
-webkit-transition:-webkit-transform 0.1s ease-in; 
-o-transition:-o-transform 0.1s ease-in;
}

.zoom_img img:hover{
-moz-transform:scale(2); 
-webkit-transform:scale(2);
-o-transform:scale(2);
}