More information is available at the community portal. You may ask questions at the help desk, village pump or on IRC channel #wikimedia-commons (webchat). You can also contact an administrator on their talk page. If you have a specific copyright question, ask at the copyright village pump.
(Removed the following post-closure comment from the subject DR)
I know that you directed your comment at the nominator, but many DRs fail, so that is certainly not the time to replace the image where used. At closure, what you suggest seems nice at first glance, but does not stand up to a close look.
First, Commons Administrators delete approximately 1,000 pages a day. Eight of us do half of that and we are barely staying ahead of a steadily increasing load. There is simply not time to do what you suggest.
Second, Commons Administrators are not by any means expert in all the fields that would be required to carry out your suggestion. Some such choices of new images would be easy, but others impossible without knowledge of the field. Therefore, policy leaves such things to the editors on each of the Wikis involved.
Third, at the moment there are Wikipedias in 281 languages. Although I don't read German, I can work well enough on a WP:DE page to replace an image, but it takes me time. In many of the 281 languages, I would not be able to do that. In many of the lesser used languages, there is no Commons Administrator who reads the language. Again, it is best to leave such to the local editors.