title: Add additional source to Image for further actions
body: <p>im trying to add an additional source to the dce-image for further actions e.g. an alternate source to perform some JavaScript actions.</p>
  
  <p>The wanted output should look like this:</p>
  
  <pre><code>&lt;img src="path/to/foo.png" data-altsrc="path/to/bar.png"&gt;
  </code></pre>
  
  <p>The problem is the dce i'm using - its iterating through the "images" like this:</p>
  
  <pre><code>&lt;f:for each="{dce:fal(field:'image', contentObject:contentObject)}" as="fileReference"&gt;
      &lt;f:image src="{fileReference.uid}" treatIdAsReference="1" /&gt;
  &lt;/f:for&gt;
  </code></pre>
  
  <p>So if I would insert multiple images to this I have no real relation between the images where i know which one is the normal-source and which one is the alternate source.</p>
  
  <p>So there was the possibility to create a section and add two fields for images which we can restrict to one image per field. But there again is the for-loop which doesn't allow me to access the source of the second image for the first image.</p>
  
  <p>It should be a visible relation between these images for the user which is working with the dce.</p>
  
  <p>Im trying to achieve something like this:</p>
  
  <pre><code>&lt;f:for each="{field.images}" as="images"&gt;
      &lt;!-- want to achieve something like this --&gt;
      &lt;f:image image="{images.foo.src}" data-altsrc="{images.bar.src}"&gt;
  
      &lt;!-- thats the normal way iterating through images --&gt;
      &lt;f:for each="{images.foo}" as="image"&gt;
          &lt;f:image image="{image}" /&gt;
      &lt;/f:for&gt;
  &lt;/f:for&gt;
  </code></pre>
  
  <p>Another idea would be to iterate first through the alternate images and store them into an array and on the main-images to access them but I have no idea if this is even possible also this will restrict the usability of the dce for the user. </p>
  
  <p>Is there any way to achieve this with dce-fluid ?</p>
  
  <p>Thanks in advance </p>