At a Glance
If you spend any time with a camera at all, you have hundreds of pictures on your PC. Actually, you may have many hundreds of them, taking up gigabytes of storage space. But somehow, some way, no matter how good you think you are at managing your photos, you've most likely have duplicate pictures taking up a substantial amount of hard disk space. Trying to weed through them all and find duplicates is a wearying, thankless task. VisiPics does it all for you, and it won't cost a penny.
Just run the VisiPics, and it finds duplicate photos--and it doesn't rely on looking for duplicate file names, but actually compares the photos themselves. Before you run the program, tell it whether you want the comparison to be Strict, Basic, or Loose, which determines how strictly the program should compare photos. It then goes about its work and shows all duplicates on the left-hand side of the screen, side by side. Mouse over any photo and its duplicate, and you'll see the photo in a preview pane. You can then make sure the photos are actually duplicates.
VisiPics deletes the duplicate photos as well; click any you want deleted. You can instead have them moved to a folder. I tested out VisiPics on seven folders with 359 photos, and it took a little more than three minutes to do its work. I used the Loose setting, and it found 68 photos it said were duplicates. About a quarter of those, though, were not actual duplicates, but rather the same scene taken from a slightly different angle. So make sure to carefully check to make sure that any duplicates are in fact duplicates.
Note: This program is donationware. It is free to try, but the author accepts and encourages donations towards further development.