Might be getting something wrong here but why are images from reference folders being compared to each other? As I understand it when selecting reference folder, all other non reference folder images are compared with one another and with the ones from reference folders. But the case is that even images in the reference folder are being compared with each other for no reason. If the point is to delete files from specific destination that can be achieved by custom select, thus making reference option unnecessary and just slows things down. In my specific case there is main dataset with ~500k images and if want to check folder with 100 images for possible duplicates before adding to the main dataset, the program compares images within reference folder making the whole process way longer than is actually needed. Again, might be wrong about this and just picked wrong options, but if not it really should be fixed.