Images in markdown now have a border surrounding them. I'm not sure if this is a bug/defect or was intentional, but the change doesn't make sense. If it was intentional, what is the justification?

.markup img {
  border: 1px solid #ccc;
  margin: 10px 0;
  max-width: 100%;
  padding: 5px;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box
}