Certainly, I'll try:
I have a ContentPart called 'Apartments' and it can have multiple images associated with it.
Ideally I would like it so that in the Admin section, when you create / edit an Apartment you are given the ability to 'Add Image'. Clicking the button will bring up the media picker for selecting / uploading an image. Once the image is added
it will be added to the list of associated images for the apartment.
You can add as many images as you want to the apartment.
You'd also be able to remove images from the apartment, perhaps by clicking a 'remove image' link next to the image name.
Hope that makes sense.
I appreciate this is quite a complicated task; essentially managing a many to many relationship from within the content part interface.