Answer:
Julie has 6 photos that she wants to rearrange.
Two of them are fixed at the middle position.
=> There are 4 photos left for rearranging.
=> This is the permutation with n = 4, k = 4.
=> The number of ways Julie can arrange the photos:
N = 4 x 3 x 2 x 1 = 24 ways
Hope this helps!
:)