The first folder I selected is full of animated gifs, and this app evidently can't process those.
Moved on to a wallpaper folder containing 18 subfolders (5,851 items). The app hung for a looong time on 50%, then finally made it to 51%, where it's been for 10 minutes.
And my fans have been racing as the app is using well over 100% CPU (highest I saw was 171%).
I just canceled the dupe-hunting process as it was going nowhere fast, but taxing my computer's resources.
Since they're wallpaper, they're large images, and two folders contain images over 3000 x 2000 pixels.
But the description says nothing about size limitations.
I then tried a folder containing many subfolders of images that I use in craigslist ads (866 items) The app went fast up to 49%, then really bogged down at 53%. It's currently at 60% and using around 130% CPU. Now it's at 63% and going very slow, taking about 7 seconds for each 1% progress (just hit 148% CPU).
My Mac is a 3GHz i7 dual-core.
It did find images that are SIMILAR, but didn't filter them as much as I'd expect, and there are no search criteria settings.
Some "duplicates" have different backgrounds or are different sizes, some have different extensions.
Some pairs are SIMILAR, but not DUPLICATES.
1. One ceramic object is on a white background, while its match is of the same subject matter but a different piece, and the colors are different and it's in front of a basket.
2. Two boxes of Budweiser steins, but they are different boxes with different colors. There were 4 different boxes in the folder, and two were selected as duplicates.
3. A pair of tower speakers with the grills on, and the same pair with one of the grills leaning against the side and the speakers showing.
4. One image showing the front of a box of Hallmark Christmas ornaments, while the other shows the box with the ornaments sitting in front of it.
Several "duplicates" are completely unrelated items:
1. The rear disc brake of a bike and a gardening book.
2. A ball cap and a package of puncture-resistant liners for a bike tire.
3. A memory card for a digital camera and a tv stand.
I guess it did a fair job on the 2nd folder, but the app needs improvement and needs to be MUCH faster and use less CPU.
IMO its WAY overpriced at $20!