MACGEEK19  This app has a great concept, but there is a few things lacking. Its a hog of the system, its interface designer should be immediately fired and the icons are horendous.   
(Version 2.0)

MEMPHISGEEK  Bad implementation of a great idea.

Would be a easy 4 star review if it were not for the constant crashes.

Not worth the money in it's current state.  
(Version 1.1.10)

SCOTT_R  Works very well, especially in v. 1.1.1, which adds many interface enhancements as well as fixing a couple of crash problems.

I don't know why anyone would have problems understanding how to use the application; it seemed quite simple to me, but some usage enhancements would be nice. Fortunately, the developer listens to suggestions--about half of the ones I've made have already been added (and I've gone a little overboard with suggestions).

Perhaps the main reason why duplicates might not be found is that, AFAIK, the application only matches duplicates of equal size. It'll find a single image multiply saved in in JPG, TIFF, and other formats, but won't match them if one is 640x480 and another is 1024x768. So far, that is the single largest drawback to an otherwise very good program (and one that is getting better).

I have a LARGE collection of photos that is rather disorganized, including sets that I cannot now identify, but might be duplicates of ones that were previously labeled and archived. However, since we're talking 89 *thousand* photos... well, just try remembering which ones! I've been able to cull out thousands of duplicates.

To explain my rating:

For "Features" to go to 5, it needs

a) the ability to match images of different sizes, and

b) the ability to rescan a particular result, adding new images. Now, you can add a new, separate directory, but can't redo already scanned directories that had new content added (matching only the new images against the existing database).

If the little interface suggestions I've made are added--e.g., when one of a pair of duplicates is deleted, for the next pair to automatically be selected even if in different folders--"Ease of Use" goes to 5.

Right now, it's helped do things I couldn't practically do before.  
(Version 1.1.1)

HANDYCAM  Would be a useful app if it actually worked. I deliberately picked a folder with duplicate images and none were detected. I had to lower the threshold to like 70%, and it then found several "duplicates", but not the real duplicate images. Not sure why it failed, but it did.  
(Version 1.1)

HANDYCAM  Tried it. A very non-intuitive interface. I couldn't really figure out how to compare the 2 dupes to figure which to delete.  
(Version 1.1)

BURNER DRAGON  This is exactly what I have been looking for but it has one hiccup. Upon comparing a 11,000+ image folder(about 8 hours scan time on a G3 333), it gets the dreaded SBBOD(Spinning beachball of death) when trying to modify the duplicate images, either trashing them or revealing in the Finder.

This is probably happening because of my slow mac. Otherwise a great app.  
(Version 1.1)

HANDYCAM  Donloaded it. If this works as advertised, I'll buy it.

So far, nothing on the Mac has been able to do this correctly. ViewIt and GraphicConverter have similarly named features, but don't really work unless the image is identical. I've thrown a folder full of extremely similar images (e.g. multiple portraits of the same person with slighly varying facial expression, and even a couple of duplicates with various crops and image sizes) and have gotten no hits in the other apps.

On the PC, there is Duplicate Image Finder, which works pretty good. But I'm on a mac. I'll try this and report back.  
(Version 1.1)

PURE DIGITAL  This is built into Viewit, and it costs half as much  
(Version 1.0.1)