An included work is someone else's copyright material that appears in your photograph. Provided the inclusion is incidental, this does not infringe. The difficulty is deciding whether incidental or deliberate copying is involved. The courts use the question 'is the copy a substantially new work?' to decide this point.

This all means you have to be careful when photographing. Putting someone up against a background of a painting might be unwise, unless the painting truly is an incidental inclusion. Buildings and scupltures are copyright, but as public works they may be photographed, although a sculpture in a private location may not.

A further consideration is the inclusion of registered trade marks such as company logos. Again, incidental inclusion is OK, but a straightforward photo of a logo may constitute an infringement. Some companies are very aggressive, the London tube 'roundel' being a famous case in point. Many stock libraries exclude any image that includes the roundel whether incidentally or not, thanks to threats of legal action.