Cubism questions

How many photographs do you think were used in the composition?
  I think there are around at least 20 give or take.
Were all of the photos taken at the same time of day?
  No, it appears that some photos have a different shading than others and are darker. 

Are there any obvious post-processing (Photoshop) enhancements?
    Yes, you can see that the artist photoshopped certain photos with a blur to make a depth perception. Some other photos are grainer than others or darker. 
Any other considerations?
  All photos aren't the same size. They appear to be cropped or smaller to give it a certain effect.