I am not quite sure about how an orphaned file or image would not be assigned to a user or attached to anything if you have the set up done correctly. Just because a users computer crashes and has not hit “save” prior, doesn’t mean the file or image they just uploaded should be floating in your database not connected to a user or assigned to “anything” ( I believe you mean it is not saved as a data field in a data type, some specific data type being “anything” )
If you are using a auto bind it has to be assigned to a thing to auto bind to that thing. Also, my understanding is that anything uploaded or created by a user is automatically assigned to that user because all data types automatically have a “created by” and dates on the data type.

I’ve read on the forum before that bubble tracks a user by using cookies, so even if a user is not signed in as a registered user, you can still track that users activity…I use this for age verification across an app.
Now, if the real issue is how do you let a user change their profile image, then decide they don’t want to change that profile image and “discard” or “cancel” changes
You should look into using custom states for “storing” the data on the page during the open session. My first thought is to on page load, load a set of custom states the user would be able to edit with their existing data loaded in the data base ( ie: current profile image )…then when they have decided to edit the image ( assuming a button press, but not needed…could just enable them to click it to edit it. workflows and creative thinking should do the trick for that ) the edited ( ie: new profile photo ) will be stored on the page in another custom state.
Then when the user presses the “save” button the custom state new photo will be used in a workflow to change the “thing” and profile image equals custom states new profile image.
So if abandoned, the custom state is deleted ( automatic ) and the pre-existing profile image remains as was.
You could do this for each and every data entry they user could edit…I assume, and have not tested this.