Exported Images Missing

I am attempting to export a large portion of our wiki into PDF form. I'm using PDF Export option so siteexport_pdf gets selected as the render engine. When I do that, the images show broken link icons. The image is linked in the following format:

{{ :ns1:ns2:ns3:image.png?800 |}}

I am able to access the images directly by their URL in my browser.

I have also tried replacing the images with a JPG to get rid of any possible issues with the alpha channel and I get the same results.

If I don't use the PDF Export option and just select dw2pdf, then the images work fine. But I prefer the layout of the siteexport_pdf. Any suggestions?

Start by reproducing the issue with the PDF Export option, the siteexport_pdf render engine, and an image using the {{ :ns1:ns2:ns3:image.png?800 |}} syntax; compare it with dw2pdf, where images work. Done means exported PDFs from siteexport_pdf display the images instead of broken link icons.

Written by the indexing model from the issue text.