Although it's not the most exciting subject, image usage rights are an extremely important part of any professional's career. At first they may seem like a major inconvenience that's only set up to make our live's tougher, but image usage rights actually help us to make more money off of every single image.
Here's a few of the main terms and what they mean:
Royalty-Free: This is a term found throughout the stock agencies that basically means the image can be sold to anyone, for any use. If you don't sell stock then this is something you likely will never have to deal with. It can even be sold for the same usages to multiple people/organizations a the same time. These images will cost far less because you are not buying any kind of exclusivity. Example: Colgate and Crest could both buy the same image for a billboard if they go royalty free, this could be an issue for them. For a lot of companies this doesn't matter.
Right's Managed: The opposite of royalty free. These images are sold for very specific uses and for a certain amount of time. This is how most photographer's will work up a contract for a specific client. The images also cost a lot more because they are exclusive for specific uses.
Exclusive/Non-Exclusive Rights: Similar to Right's Managed and Royalty Free, these are the terms that you will use with clients specifically, not with stock agencies. Say you want to do a shoot for a client, give them photos to use for their firm, and then sell the photos to another non-related company. You would give both companies the non-exclusive rights to the images from the shoot. You will also want to charge less because the companies don't need exclusivity and you will be selling the images multiple times. Many companies that are hiring you will expect exclusive rights up front to preserve the images just for their own usage. This is when you want to set a time limit on those image.
Timed Usage Rights: For most contracts, it's best to give exclusive terms for a certain amount of time that you will work out with the client. The longer the time frame, the more the images will cost. In your contract or on your invoice, you would say, "2 years exclusive rights." By doing this, the images all become yours again after 2 years. This works great because you can sell the images again, or upload them to your stock agency at the end of the 2 years for sale.
Location Based Rights: Sometimes you'll have an image that you will sell rights to for United States exclusively. This means that you can also sell the image in China, or Spain, etc… Yet another way, to profit more from the same images.
Specific Usage Rights: Companies will often only need web rights, or text book rights, or print rights. If this is the case, specify this in the contract that the image is Exclusive for web use only. This means that the client can only use the image for web, and you can sell it to another client as well for print usages or other usages.
As you can see these rights will help you to figure out ways of selling the images again and again. It's far better to be in a 2 year contract, then to just give away images forever. Keep track of all your contracts, and remember to sell images again when they expire!
For pricing information and more details on usage rights, a great place to look is gettyimages.com. This is a direct link to my images on the Getty site. You can click on one and go through the purchase process (without actually buying unless you want the image!) to see how much they charge for specific usages. With clients I typically start here to get a good idea of what to charge, and then drop it back a bit to come up with a more realistic amount.