Copying illustrations, diagrams or photographs requires the permission of the copyright owner. Posting a document on the world wide web is a public display of the work, which is among the rights exclusively reserved to the owners of the copyrighted work. Law requires that the author of a website, book, etc. ask the copyright owner for permission before displaying or use any copyrighted work. The burden is on the copier to ask permission. It is within the rights of the copyright owner to start with litigation immediately on discovering unauthorized use of copyrighted material.