I know we all know celebrity photos get retouched, a whole lot, before they appear in magazines. (yes, even rags like InStyle retouch, I believe.) However, it's one thing to know that and quite another to see the befores and afters. (And then a whole 'nother thing to try to disassociate your own body issues from the images constantly being beamed at you in the media ... but anyway.) This site should help. http://iwanexstudio.com/. Click on the portfolios section. The whole site is flash but it's worth the aggro.
I suggest you take a close look at the work done on skin (very often in the afters it's lit up until it glows! It's not just the removal of lines, although there's plenty of that. Reddish people get yellower, freckled people become milky, lips and eyes get shine added until they sparkle. Cate Blanchett's picture has all of these things happening.) Look, also, at the work done on bodies (skinny girls are given more curves, curvy girls are airbrushed down a couple of sizes - Kelly Clarkson's picture is a great example). Halle Berry is one of the few pictures who looks just as flawless before and after, although it looks to me like the "before" has been de-flawed. Do I even need to tell you that both Halle Berry and Beyonce get lighter in the after photos? Sigh.
Scary. And also, this is a good explanation for why Britney Spears looks just fine in regular magazine photos and really horrible when you see candids of her in The Enquirer (read in line at the grocery store only, of course.)