title: Validate input file image array in laravel 4
body: <p>I have a form like this that can have multiples images[] field:</p>
  
  <pre><code>{{ Form::open(array('url' =&gt; 'foo/bar', 'files' =&gt; true)) }}
      &lt;input type="file" name="images[]"&gt;
  {{ Form::close() }}
  </code></pre>
  
  <p>How can I validate this field with laravel 4 validation?
  I tried this rule but it didn't work:</p>
  
  <pre><code>$rules = array('images[]' =&gt; 'required|image');
  </code></pre>