In order to track image views more meaningfully: https://www.mediawiki.org/wiki/Requests_for_comment/Media_file_request_counts#by_context we should add a url parameter to image requests in order to tell apart the general context the image is in. Varnish frontends should then translate that custom parameter to an X-Analytics header: https://wikitech.wikimedia.org/wiki/X-Analytics for the information to make it all the way to the cache logs.
We should avoid tracking too many different contexts to keep client side cache fragmentation minimal.