LS, There is a bot in use that finds pictures in wikipedias that are linked to an article. It allows you to select among the wikipedias that have a picture and, it will upload the picture for you including the messages associated with the picture on the original picture.
The problem is that these messages may be in a language that is not readily understood. To compensate for that, it might be an idea to use messages in all wikipedia's that have a localised content. In the en:wikipedia and the nl:wikipedia for instance several messages exist to tell about copyright. My proposal is to make the names and content of all existing messages the same and, translate them to the wikipedia's. Meta would be an ideal place for such an endeavour ??
Thanks, Gerard Meijssen