While reviewing thumbnail container improvements, we occasionally faced a bunch of ClientAbortExceptions (broken pipe) —only when using Firefox. Turns out there is not much we can do here, all required images are served fine, so we should just ignore those, like we do in other places.

For now we just use the same snippet as in other servlets (e.g. ResourcesServlet, ClasspathSpool), until we come up with a streamlined solution somewhere around the filter chain (see related ticket).