When rendered, ezimage links are generated with an absolute URL and this might be problematic in various configurations (e.g;: if a Reverse Proxy is used in front of the website to change host, port, scheme,...).

This issue has been discussed here: http://share.ez.no/forums/ez-publish-5-platform/how-to-instruct-ez-publish-5-to-work-with-relative-url-on-ezimage-rendered-images