Originally Posted by AlienQ

If you intend to use someone's copyrighted work, unless the use is considered a fair use, you must obtain that person's written permission. Under federal copyright law, only the copyright owner or someone acting with the owner's authority, such as a publisher, can grant that permission. While not every unauthorized use of a copyrighted work is an infringement, whenever you use another person's words, illustrations, photographs, charts or graphs in your own work you must be sensitive to the risk of infringing that individual's copyright.