com.neatdecisions.Detwinner
Detwinner is a tool to search and remove exact file duplicates and similar images.
You can search for either exact duplicates (100% byte-to-byte match is ensured by the special hash function) or similar images (Detwinner generates groups of images that look alike using similarity level specified by you). You can also narrow your search by specifying file size, attributes and regular expressions.
Smart selection tools provide numerous options for batch selection of files which should be deleted. Instant preview allows you to be confident in your choice.
Files can be deleted permanently, to the trash bin or moved to the backup folder.
Latest reviews
Brilliant app, just brilliant - but a warning. It selects duplicates faultlessly and not sure how it discovers "similar files" - that's like some kind of magic and I can't fault that either. When it comes to deleting files using "Smart select" it works every time but... it has a really, really annoying flaw. Three times now I've spent and hour plus manually selecting files only to have it un-select all my choices when I press "delete" and also not delete the files. Not good for the blood pressure. Since the last update was three years ago I'm making a wild guess this might not change. Of course I still appreciate the developers' efforts and I'll still use it but only for exact duplicates and if smart select will cut it. In case the dev reads this - it was probably in th order of 200+ files selected for deletion each time in mainly groups of 2 and 3 and a few groups of more.
Excellent app with almost all you need to remove duplicates, especially photos (you can see preview of the images or first 1kb of data).
I believe that it is simple, effective and have potential to safe some space. It is lite user friendly. I played around on with a small file, and get to know the functions. It worked ok. However, I am not sold on large files because it seems to be taking an entire day to scan a 1T external drive, and after I selected the files to be deleted, it has been stuck in moving to the trash bin for over 3 hours. So I guess for small files, it ok, for large one, you have to check.