i am comparing images with each other here is the code for it.

for (int i=0; i<arrImageData.count; i++) { for (int j=i+1; j<arrImageData.count; j++) { if ([arrImageData[i]isEqualToData:arrImageData[j]]) { [arrImages addObject:arrImage[i]]; } } } 

now problem is when number of images increase it takes too much time to calculate.is there any better solution for it?