DITA Dynamic HTML5 Filters

I have two images.  One for product=iMX350 and another for product=iMX950.

My document is structured as follows:

<fig
frame="all" product="iMX350">
<title>Product Label</title>
<image
href="../../../../iMX_Common/Installation_Guide/assets/iMX350%20Label%20Dual%20MAC.png"
height="320.639pt" width="426.240pt" conkeyref="graphics/iMX350_label"
/>
</fig>
<fig frame="all" product="iMX950">
<title>Product Label</title>
<image
href="../../../../iMX_Common/Installation_Guide/assets/iMX950%20Label%20Dual%20MAC.png"
height="320.639pt" width="426.240pt" conkeyref="graphics/iMX950_label"
/>

</fig>

I have a dynamic filter set up on the product attribute.  I am finding that only the figure text is being filterd.  Despite being nested within the figure tag, both images are always displayed.  Why is the filter not having any effect on the image content?