Nginx reverse proxy with cache - dynamic images do not display

Hi,

I set up this configuration: http://pastebin.com/R65RiX5n

The images that are served by a servelet do not appear. Do you know
how I can fix this so that images served by servelets (dotContent,
contentAssets, or /resize_image) work? So the image tags on the HTML
are:

I appreciate any suggestions.

Alex