1. Insert a Calculated Value control where you want the image to show. Have
it calculated as something like `concat(' <https://server/image-',
encode-for-uri(xxf:get-request-parameter('code')), '.png> ')`. Note the use
of `encode-for-uri()` to avoid XSS.
2. Check that when you run the form, the markup for the image shows
3. Edit the source of the form to add on the `<xf:output>` that corresponds
to your control an attribute `mediatype="text/html"`.