Preferences

Filter Hardness: The higher is this setting, the "harder" is the filter (In other words, the less results you get). Most pictures of the same quality match at 100% even if the format is different (PNG and JPG for example.). However, if you want to make a PNG match with a lower quality JPG, you will have to set the filer hardness to lower than 100. The default, 95, is a sweet spot.

Match scaled pictures together: If you check this box, pictures of different dimensions will be allowed in the same duplicate group.

Can mix file kind: If you check this box, duplicate groups are allowed to have files with different extensions. If you don't check it, well, they aren't!

Use regular expressions when filtering: If you check this box, the filtering feature will treat your filter query as a regular expression. Explaining them is beyond the scope of this document. A good place to start learning it is www.regular-expressions.info.

Remove empty folders after delete or move: When this option is enabled, folders are deleted after a file is deleted or moved and the folder is empty.

Copy and Move: Determines how the Copy and Move operations (in the Action menu) will behave.

• Right in destination: All files will be sent directly in the selected destination, without trying to recreate the source path at all.
• Recreate relative path: The source file's path will be re-created in the destination directory up to the root selection in the Directories panel. For example, if you added "/Users/foobar/Picture" to your Directories panel and you move "/Users/foobar/Picture/2006/06/photo.jpg" to the destination "/Users/foobar/MyDestination", the final destination for the file will be "/Users/foobar/MyDestination/2006/06" ("/Users/foobar/Picture" has been trimmed from source's path in the final destination.).
• Recreate absolute path: The source file's path will be re-created in the destination directory in it's entirety. For example, if you move "/Users/foobar/Picture/2006/06/photo.jpg" to the destination "/Users/foobar/MyDestination", the final destination for the file will be "/Users/foobar/MyDestination/Users/foobar/Picture/2006/06".

In all cases, dupeGuru PE nicely handles naming conflicts by prepending a number to the destination filename if the filename already exists in the destination.