I'd been planning to do this for some time now but never got around to it.
Everyone assumes that bloggers will use any image they find, be it through Google or from the story's original source or whatever. I know I do. I also know that when other blogs repost myoriginal stories they use my photos, and I'm quite happy to have them do it.
But I also want to be proactive in this so I'm going to release all the photos under a CC-BY-NC license. Basically anyone can use the photos for any non commercial purpose so long as they give me attribution. And in case you were wondering a blog post with adverts on the same page is _not_ a commercial purpose, so bloggers can indeed use the images.
P.S. If anyone thinks this is a bad idea, please let me know.