title: Prevent output escaping in Twig function extension
body: <p>I have created a Twig extension:</p>
  
  <pre><code>{{ image ("image.png", 200) }}
  </code></pre>
  
  <p>HI know I can just do</p>
  
  <pre><code>{{ image ("image.png", 200)|raw }}
  </code></pre>
  
  <p>...but I would prefer to use PHP code so that everything (from this 'image' extension) is not escaped.</p>
  
  <p>I can't see this possible.</p>
  
  <p>I know I can prevent all output escaping in Twig, but I just want this one extension not to escape output, and everything else to do so.</p>