I don't know how useful this is but I use The Gimp to help with my photos. But there are a couple of reasons for that:
1. I use Linux as my os
2. I am a frigging cheapskate and will not pay for Photoshop (The Gimp is free, as in free beer)
I'm not a Linux fanboy (really, I'm not) but there are a lot of free (as in beer) programmes for touching up photos. I've got one that makes me look intelligent, wealthy and successful with women (okay, that's liquor, I lied )
"Unbloodybreakable" DCI Gene Hunt, 2008