Tips on Using Stock Photos
Generic images
You don't want to select a photo that has been used repeatedly or looks staged with overly-posed subjects. You want to show people with more candid expressions. An authentic image in a realistic setting works best.
Ignoring the fact that a business person at a computer can be a bit of a cliché, you can see the photo on the left creates a subtle and more real reaction and expression, as the subject seems to be focused on what he is doing and reacting to it. In comparison, the photo on the right looks staged like a shot in a catalog.
It is also important for your image to reflect the main message of your material. For example, if you are talking about catching up on reading for work over the weekend, like Kelly did recently, an image that makes sense is a person reading in casual attire and a relaxed setting versus in a suit in an office.
Product photos
Inserting products on a stock photo background is one of the most common techniques used. But if the tactic is obvious, it will look terrible. It can be a tedious process to make the image look natural by adjusting shadows, highlights and the overall scene lighting but it is well-worth the time invested.
You don't want to feature your product this way.
You can see many mistakes in the example above. First, there is a white line on the left that doesn't match well with the car's angle. Second, the lighting of the car looks wrong since the sky is somewhat orange. Lastly, the car should be on the right side of the road if you are targeting North American customers.
On the other hand, the example below exhibits the best way to add in your product into a scene with consistent lighting, color and a perfect angle.