A citation is a reference to a published or unpublished source. It is permitted to quote a relevant part of the work of someone else with acknowledgement. A quote should be relevant and functional within the context in which it is placed.
Images can also be used as quotations under certain circumstances. However, different requirements are set for citing. The most important are:
- The quotation must serve to clarify a particular argument or story
- the number of quotations and the size of the quotation must be reasonable
- the quotation must not have the predominant of ‘decoration'
the portrait right is one aspect of the Dutch Copyright Law and that means:
"The right to control the use of one's image and if the portrait was taken by order of the photographed person, you do not have permission to use the picture. If this is not the case, the picture may be used except when reasonable interest is damaged."
if in doubt, always ask written permission. But if you have an image with people in public space, you are allowed to use the image without asking permission.
Work of arts such as statues or paintings are protected by copyright. Using a picture of a painting or statue is not allowed without permission of the artist. But for a work of art which is located permanently in a public space (public road, railway station, shopping mall, and a hall of a town hall) pictures may be taken and used. It is important that the work is displayed as it can be seen in its surroundings.
However, a museum or a school is not a public place so pictures made in a museum or a school cannot be used, except artwork in public domain. if you want to use an image with art work in your education, perhaps you can cite that picture.