Karen, you may post photos you have taken or to which you own the copyright. Anything else needs to be copyright-free/public domain or have prior permission from the copyright owner please (state this in the post as well to save us asking about it.)
Out of copyright items are fine, of course, but it's not always easy to tell if something's out of copyright. If in doubt, err on the side of caution and don't include the image.
You can always ask us for advice about particular instances. Email one of the Global Moderators (see sign under our names to the left) or use the Report to Moderator option to refer to a particular topic/post. As always, shout if you get stuck.
