I got a solution, don't know if it's the best one though. In the proxy that loads the images, I created a dictionary object that stores each loader for the image. so when a notification is sent, a new entry is created in the dictionary and the loader is stored in that. then, when it has loaded, a notification is sent passing the loader.content and the loader.name as a type for the notification.
the mediator that actually adds the links then checks whether it is the correct notification based on the type and if it is, it adds the image to the link. works but don't know if best solution. Any tips, suggestions??