title: filter a List according to multiple contains
body: <p>I want to filter a <code>List</code>, and I only want to keep a string if the string contains <code>.jpg</code>,<code>.jpeg</code> or <code>.png</code>:</p>
  
  <pre><code>scala&gt;  var list = List[String]("a1.png","a2.amr","a3.png","a4.jpg","a5.jpeg","a6.mp4","a7.amr","a9.mov","a10.wmv")
  list: List[String] = List(a1.png, a2.amr, a3.png, a4.jpg, a5.jpeg, a6.mp4, a7.amr, a9.mov, a10.wmv)
  </code></pre>
  
  <p>I am not finding that <code>.contains</code> will help me!</p>
  
  <p>Required output:</p>
  
  <pre><code>List("a1.png","a3.png","a4.jpg","a5.jpeg")
  </code></pre>