Solved by ptrblck in post #4 
              
              
                I’m not sure if there is another way to optimize this. 
Assuming you are dealing with N images, your model would have to calculate 
N + N-1 + N-2 + ... + 1 = (N+1) * N / 2 comparisons. 
You could speed it up using batches, but if I understand your explanation correctly, you are avoiding unnecessary …