[CF] CFImage WriteToBrowser issue

<cfimage action="read" source="thermo-empty.png" name="myThermo">
<cfdump var="#myThermo#">
<cfimage source="#myThermo#" action="writeToBrowser">

I have the above code. The CFdump returns information about the image, as it should, but the img tag that coldfusion generates looks like this

<img alt="" src="/CFFileServlet/_cf_image/_cfimg-3324082959714872781.PNG">

and doesn’t load an image.

What am I doing wrong?