Msg#: 4305279 posted 10:35 am on Apr 28, 2011 (gmt 0)
For printed or "static" (e.g. PNG, PDF, etc) content, use the date it was created.
For a dynamic website use 2005-nnnn where 2005 is the year of first publishing and nnnn is dynamically updated on every page view using the PHP date function. Don't use JS as searchengines will not see that text.
Copyright is indeed automatic. But having one's copyright notice on an image can be extremely helpful when notifying a plagiarist's host. "See? There's my name and copyright notice right in the image and the article's coding!"