A search revealed:
"Copyright on the web seems to be a difficult concept for some people to understand. But it's really simple: If you did not write or create the article, graphic, or data that you found, then you need permission from the owner before you can copy it. Remember, when you use someone's graphic, HTML, or text without permission, you are stealing, and they can take action against you."
And
"When is Copying Something an Infringement?
The most common types of copyright infringement on the web are images being used on web sites other than the owners. It doesn't matter if you copy the image to your web server or point to it on their web server. If you use an image on your web site that you didn't create, you must get permission from the owner. It is also common for the text, HTML, and script elements of a page to be taken and reused. If you have not gotten permission, you have violated the owner's copyright.
Many companies take this type of infringement very seriously. About, for instance, has a legal team that handles copyright infringement, and the Fox TV network is very diligent in searching out fan sites that use their images and music and will demand that the copyrighted material be removed."
General it seems the default assumed if not shown is anything posted on the web is copyrighted unless specifically indicated otherwise.
You can remove any copy right you have to a picture for instances but apparently this is not easy to do so anyone intending to reuse your picture should check the copyright status before use.
So it would seem they should not be using it without your permission.
