This sounds interesting.

A google search on "photo challenge" brings up a number of sites.

http://www.dpchallenge.com/ is one. These appear to be weekly and recently have covered "Ansel Adams," "Glasses," "Personality," and more. If you do an image search on this site for "change" you get quite a variety of photos, not all of them related to "going through a change but inspiring nonetheless.

Another is http://www.photofriday.com/challenges.php.

A google image search for "changing" is another source for inspiration.