title: Laravel Call to a member function isValid() on null
body: <p>In my project users can upload stuff and attach an image.
  I have a controller where I do a isValid check on the file input. Everything works great as long as you select a file. When I don't select a file I get this error</p>
  
  <pre><code>Call to a member function isValid() on null
  </code></pre>
  
  <p>On this line of code:</p>
  
  <pre><code>if (Input::file('image')-&gt;isValid())
  </code></pre>
  
  <p>The error is obvious since I don't select an image but I actually have no idea how I can fix this.</p>
  
  <p>If anyone can help I'd be very happy :)
  Thanks in advance!</p>