function fixSize(target) {

  const $parent = $(target);

  const $child = $parent.children();

  const pWidth = parseInt($parent.width(), 10);

  const pHeight = parseInt($parent.height(), 10);

  const cWidth = parseInt($child.width(), 10);

  const cHeight = parseInt($child.height(), 10);

  const nWidth = cWidth*pHeight/cHeight

  const nHeight = cHeight*pWidth/cWidth

  const centerX = (nWidth-pWidth)/2;

  const centerY = (nHeight-pHeight)/2;

  if(cHeight*pWidth/cWidth < pHeight) {

    $child.attr("style", "width: "+cWidth*pHeight/cHeight+"px; height: "+pHeight+"px; margin-left: -"+centerX+"px");

  }

  else {

    $child.attr("style", "width: "+pWidth+"px; height: "+cHeight*pWidth/cWidth+"px; margin-top: -"+centerY+"px");

  }

}