Here are some links from various posts and some that you may just find interesting:

http://www.publicartscotland.com

http://www.rcahms.gov.uk/

http://www.edinphoto.org.uk/index.htm

http://www.inglebygallery.com/

http://www.flickr.com/creativecommons/

http://www.geograph.org.uk/

http://catrionablackdinham.wordpress.com/

http://aajpress.wordpress.com/

http://playablespaces.wordpress.com/

http://thetoomuchfunclub.com/

http://curiogalleryedinburgh.wordpress.com/