With all of your marked photos laid out in the browser, you can use the buttons in the lower-left corner to move them all to the trash, move and rename them, or copy and rename them. When you are happy with the results, click the Show Marked button in the lower-left corner. Using the two buttons at the top - Group List and Face-to-Face - you can view your photos by group or view two side-by-side for closer inspection. Double click on each photo in this view to toggle from marked and unmarked.

You will then see your photos arranged by groups, where all but one of the photos in each group is marked for deletion. Say yes by clicking the Auto Mark button. When it has finished, a pop-up window will appear, asking if you'd like the app to mark your photos. When you have your photos in the browser and your settings just so, click the Compare button at the bottom of the app, and PhotoSweeper will begin comparing your selection. Set it more toward Exact Match if you feel PhotoSweeper is being too choosy. At the bottom of this right-hand panel is a slider to adjust the Matching Level. In settings, you can choose to search only for duplicates or a handful of methods to root out needlessly similar photos.

To the right of this large browser space is panel to view the settings for your comparison method or image info. Choose a folder or group of photos and drag it to PhotoSweeper's browser. To add photos to PhotoSweeper, use the Media Browser or Add Photos button in the lower-left corner. The app features a large browser for your photos, but it will do the comparison work itself.

You can also drag and drop photos or folders from your desktop. PhotoSweeper works with iPhoto, Aperture, and Adobe Lightroom. The app costs $9.99 in the Mac App Store. PhotoSweeper for Mac identifies duplicate and similar photos and lets you dump the ones you don't need in the trash. Unless you dutifully manage your photo library and cull the extra shots from each photo shoot, your library quickly becomes difficult to navigate and your hard drive cluttered. Freed from the cost of purchasing and developing film, digital photographers can take multiple shots of the same scene in an attempt to capture the perfect shot. Digital photography is a blessing and a curse.

Find duplicate photos in apple photos