Well to implement that you have multiple ways. I'm gonna tell you one.
As I understand there is a fixed number of attributes what you can do is:
- The user can have multiple custom images.
- Add to the custom image entity an identifier attribute to know exactly which "attribute" represents. (It can be an enumaration, number, string. For example: "Profile Pic")
- On the pages, check if there is an image for that user (as they are linked) with that identifier- If yes you show the previous image - If not you just allow the user to upload a new one.
- When you add a new one, you need to set the proper identifier, so next time you will know that there is a image for that.
I don't know if this helps, if you have any other question let me know!
Maybe I didn't understand your question so well, but this how i will do it
e.g. User entity 1-* Picture (Sys.Image)
Attribute - FullName, Birthday, Pic1, Pic2
On Edit profile you will have field that need to be filled e.g. Birthday add OnChange function that will create one new entity Picture and it's will be associated to User then with this flow you will make sure that all filed that user enter will have picture, you can always add more custom logic if neede.
hope this help you
Best regards, Slavko