`image in page.media.images` Problem/Question

In the following:

{% for image in page.media.images | slice(0,1) %}

      {% if image is not null %}

         {{ image.cropZoom(500, 500).html() }}     
      {% else %}

         <img src="{{ theme_url }}/css/images/square-placeholder.png">

      {% endif %}

{% endfor %}

I was expecting image to be null if there were no images attached to the page. No? Advice appreciated because no matter how I word the if the image is always something. How do I dump the variable or array?

if there are no images available, then the for loop is not even entered. you would need to check to see if page.media.images is empty or length == 0.

AHHHH thank you!