We do not sell pictures. We license their use. In addition, we collect fees for assignments and other services, we sometimes resell products (such as film, prints, DVDs or other media) and we receive reimbursement for expenses incurred while completing and delivering assignments and images. Written agreements should govern all of these transactions. And you should consult your attorney regarding such agreements.
A contract should answer at least the following questions:
What are you required to deliver to the client? In what form?
Who is responsible for mistakes, accidents or oversights that might result in liability or lawsuits from others?
What will you be paid?
When and how?
What rights to your original images are released to the client (the license)?
What happens if an assignment is cancelled at the last minute?
Can your client license your photographs to a third party, such as a wire service?
Answers to all of these questions and more belong in written contracts, which is why it is so critical to understand contract language. Contracts should be negotiated and agreed on before a assignment or usage license is confirmed. A good contract protects you and your client. Remember that a contract provided by a client is designed to protect the client. You need to be sure it does not endanger you.