Steps I think were used:
1. The image started out with a flat image
2. Areas of the picture were chosen to be replaced with other pictures
3. The pictures chosen to replace were cropped and cut to fit the dimensions of the squares
4. The images were pasted into the document and resized to fit a location.
Q1. McNally must have taken many pictures, if I had to guess I would say maybe 46 were taken, but only 7 were used.
Q2. Probably not, in order to show the different dimensions of the image he probably took the pictures at different times of the day.
Q3. The colors seem to be enhanced a bit and the blur.
Q4. No.
