The collection of photographs taken during the German Occupation and administered by the Nederlands Fotomuseum mainly originates from the study and the 1995 publication of the same name: De illegale camera 1940-1945, Nederlandse fotografie tijdens de Duitse bezetting (The Illegal Camera 1940-1945, Dutch Photography during the German Occupation) by Veronica Hekking and Flip Bool. Whereas pictures of the German Occupation had mainly been used previously to illustrate a text, the above publication calls for photography to be acknowledged as a historic source.

In many collections of war photographs, the photographer's name is not always known, but the reverse is true of the collection of the Nederlands Fotomuseum, and the photographs can be evaluated in the broader context of the historic background of the image they present and the photographer’s working life.

The collection consists of 4738 negatives and album pages documenting the effects of the German Occupation.