Six photographers A, B, C, D, E and F each submitted 24 photographs, distributing them among four magazines I, II, III and IV. The bar chart shows the number of photographs each photographer submitted to magazines I and II. The numbers submitted to magazines III and IV are not shown. The following additional facts are known. 1. Every count (including 0) is a multiple of 4. 2. Magazine IV received twice as many photographs in total as magazine III. 3. Photographer A submitted a different number of photographs to each of the four magazines. 4. Exactly one photographer submitted photographs to all four magazines. 5. Photographer D submitted more photographs to magazine IV than to magazine III. 6. Photographer F submitted half of his photographs to magazine IV.
What was the total number of photographs published by magazine IV?