Google's Feedback-ID Header

Since we're talking about Google? Does MW pass " Cache-Control: no-cache, max-age=0" on tracking images since the accessing Gmail through the web and mobile interfaces caches the images?
@Mxyzptlk FishStix - Google caches all images, regardless from where you access them and regardless of headers. It's been a long discussion about this at that time, but for now we are all fine with the way gmail works.

As the images are served directly from the server(don't go through PHP), you can as well .htaccess them with right expiration.
Did the Feedback-ID get added? I tried to add a custom header for it but the colons get stripped out so can't use it

Header Tag / Value
Feedback-ID / [CAMPAIGN_UID]:[SUBSCRIBER_UID]:notify:mymta
@Brett - yes feedback id header is added but since that version of mailwizz containing it hasn't been released yet, you'll have to wait a bit more.