I have to explain to a user of wikipedia NL that the image she has made by taking a frame from a televison broadcast not can be used. But it is very difficult to inforce a strong copyright policy when the other wikipedias are not taking the image copyright more serious.
Instead of deleting images copied from the English Wikipedia which you suspect are violations, I suggest trying to educate your users to add a more comprehensive note like
"From the English Wikipedia, original photo in the public domain (NASA)." "From the English Wikipedia, by en:User:Foo, contributed under the GNU FDL." "From the English Wikipedia, used there under US fair use law." "From the English Wikipedia, no source cited."
Then people who care about copyright violations can inquire on the English Wikipedia (e.g. put a notice on the user's talk page) where no source has been cited. In fair use cases, it has to be checked if a local equivalent exists (usually the case in European countries). In cases of violations, it should be easy to get the respective image deleted from en by simply putting it on the Votes for deletion page. Then it should be equally easy to delete it from the other Wikipedias which use it.
Regards,
Erik