.img_left {
  float:left;
  margin-right:7px;
}

.img_right{
  float:right;
  margin-left:7px;
}

a.img_opacity:hover {
  background-color: transparent;
}

a.img_opacity img:hover {
  opacity:0.7;
}

.twocolumns{
  -webkit-column-count: 2;
  -moz-column-count: 2;
  column-count: 2;
}

.threecolumns{
  -webkit-column-count: 3;
  -moz-column-count: 3;
  column-count: 3;
}

.fourcolumns{
  -webkit-column-count: 4;
  -moz-column-count: 4;
  column-count: 4;
}

.columnbreak {
  display: inline-block;
}