Before and after is rather compelling. Below are some of my before and afters, showing my photoshop work. NOTE: much of this is subtle. Yes, that is a good thing.
Created for an event. If you look on the venue's marquee you will even see something invented. More art deco vs subtle. TONS of small edits.. very fun to do.
For an exercise web site. The original stock photo had an out-of-date color scheme, plus I needed more bright blue to match my client's brand. The guy's shirt, the woman's shirt, even the water bottle needed to be updated. The all over tone was flat, which I enhanced.
More work than it looks, this paper company had very specific requests about this photo. The fluorescent light had to be removed (which left gaping holes that needed to be artfully filled). Some recessed lights were also removed.