Simplifying similar functions using a hover state with different div content
The recommended way is to use event delegation:

$('.test, .testx, .testxy, .testxyz')
  .on('mouseover', 'img', function (e) {
    TweenLite.to($(e.delegateTarget).find('span'), 1.5, {opacity:1});
  }).on('mouseout', 'img', function (e) {
    TweenLite.to($(e.delegateTarget).find('span'), 1.5, {opacity:0});
  });


This will add the mouseover and mouseout events to all img tags within your parent elements. When the event is fired e.delegateTarget will be the parent element, so we can easily search for the span.