The rules for clean-up uploaded images

I am agree that the uploaded images in user’s accounts has to be clean-up from time to time, but can somebody explain me the rules for such an activity.

The uploaded by me images were cleaned-up but t a first glance in a fortuitous principle. Why I think so? Some of the recently uploaded images ware cleaned-up but some older still remain unattached. I would give preferences that the older have to be cleaned-up first but the new ones to stay in my account for some reasonable time, to be able to tune-up some of the current measurements.

The only thing that makes me happy now is that the created by me sequences (in Administration section) are still there and I hope nobody will cleaned them up.

Velimir Popov

(PVEA)