Image cache headers are sometimes provided by Drupal, sometimes by Apache

I also propose renaming the proxy_cache_maximum_age option to cache_max_age since it's misleading: that max-age is not only used in case of reverse proxies, but every time an image is served by drimage.

I changed DrImageController to disable caching in case the option is set to 0, but that doesn't fix everything yet. Redirect responses caused by PathProcessorImageStyles are still being cached, which causes any subsequent page loads to keep redirecting to the drimage endpoint with a path in the format $path_prefix . $width . '/' . $height . '/' . $fid . '/' . $iwc_id . '/' . $format, not allowing Apache to directly serve the generated file. I'll try to add a response subscriber that disables caching for those redirect responses.

Okay, so this works:

1. First request is to /nl/drimage/1500/0/67/event_header/sites/default/files/media/images/Agenda_Detail%20Page%204_%20Study%20Spaces%20Zomer%20-%20Content.jpg.webp, redirects to /nl/drimage/1500/0/67/event_header/webp (served by Drupal, not cached)
2. Second request is to /nl/drimage/1500/0/67/event_header/webp, serves the image (served by Drupal, not cached)
3. After reloading the page, first request is again to /nl/drimage/1500/0/67/event_header/sites/default/files/media/images/Agenda_Detail%20Page%204_%20Study%20Spaces%20Zomer%20-%20Content.jpg.webp, but this time served by Apache and still not cached
4. After reloading the page, the request is served from browser cache

This could still be improved: if we could get rid of PathProcessorImageStyles, the second request could serve the image and the image would be served from cache during the second page load instead of during the third. This is only the case for the first user loading the image if it hasn't been generated yet though, so might not be worth the effort.

Automatically closed - issue fixed for 2 weeks with no activity.