On the re-use of images, you can do what you want with images labelled as public domain. For creative commons licenses you have to check which one applies. See http://creativecommons.org/about/licenses/ for a summary of the licenses (or use the Flickr link http://www.flickr.com/creativecommons/. At one end of the spectrum there is “Attribution” which “lets others distribute, remix, tweak, and build upon your work, even commercially, as long as they credit you for the original creation.”. At the other end is “Attribution Non-Commercial No Derivatives” which “allows others to download your works and share them with others as long as they mention you and link back to you, but they can’t change them in any way or use them commercially.”

So all images sourced via above sites can be re used with issue unless otherwise stated?