Show Child Image When Mouse Over on Text in HTML

CSS isn't going to be able to call other elements like that, you'll need to use JavaScript to reach beyond a child or sibling selector.

You could try something like this:

  1. .hover_img a { position:relative; }  
  2. .hover_img a span { position:absolute; display:none; z-index:99; }  
  3. .hover_img a:hover span { display:block; }  
Then,
  1. <div class="hover_img">  
  2.      <a href="#">Show Image<span><img src="images/01.png" alt="image" height="100" /></span></a>  
  3. </div>