Right now, if you update your content box, you have to manually delete and reload the content box in all mailings that already contain that content box. Adding dynamic content only works with text, not with pictures. If you are working on several mailings at the same time and have group automations and other mailings, this is quite a lot to delete and reload.

How it should be: You change the content box and the change applies itself on all outgoing mailings that contain this content box.