It is a fairly common mistake that  clients believe that they may own an image and have unlimited exclusive rights and the copyright, when really that is not what they agreed to.  Education, is the key to help prevent problems. Know what the terms mean before you sign. Do not assume anything.

 Some agreements state they can only be used on certain projects or web sites.  Example, not to be used on the mirror sites listed on the website.  Read your agreements to make sure what your rights are to the images you are using. Example, exclusive rights MUST ALWAYS be in writing in the agreement with a time limit. If there is no date, you may have something known as a Royalty-Free right, that too should be in writing. 

Knowing what you agreed to, not only protects you from wrongfully usage of an image and upsetting the photographer, but it gives the photographer a better understanding what the client is wanting the image for. That way a fair price of usage can be made. If you are getting something for FREE, chances are you would not have an exclusive to the image. If you are paying a large fee, than you may have an Exclusive, but with a time limit. If you have a small fee, example, $200, you may have a one time usage right to use the image.  Make sure what  you say you have is IN WRITING, you can not go by verbal agreements especially if you are talking Exclusive or Unlimited rights.

It's almost NEVER that the copyright is transferred UNLESS you agree in writing to a TRANSFER OF OWNERSHIP. Transfer of ownership is like removing the soul from the artist. There are few reasons why a client would ever need to OWN the work.  You could not buy an original painting from a famous artist and remove his signature and add yours. Nor would you buy a CD and burn your favorite songs and sell them as your own songs. Copyright last 70 years AFTER the authors death.

Images do NOT become property even to those who have exclusive or unlimited rights. The ownership belongs to the artist.