In the past was the case that when there was a image on commons, people could
find it as well by typing "image:Name.extention" in their own wiki, and got a
discriptionpage witht the image, saying the image was availeble via Wikimedia
Commons. When you type now for instance "Image:Community.gif" in en.wikipedia,
while it does exist on commons, see
http://commons.wikimedia.org/wiki/Image:Community.gif . I think this is a bug
that entered during last updates. Some days ago the function was there i think.