Bug: Update imgaes can by only done, if item was created

[jedie]

1. start add a new item
2. add a image
3. try to save

Then you will get the error RelatedObjectDoesNotExist: ItemImageModel has no user.
The problem: Ithe Item instance will have only a user attached after a save call.

work-a-round:

1. start add a new item
2. use "Save and continue editing"
3. add image(s)
4. Save