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Dup 2.1: Smart Auto-Keep, Cross-Format Matching, and Photo Quality Ratings

Dup 2.0 introduced face detection, dev cache cleanup, and a complete redesign. Since then, I've been listening to what users actually do after they find duplicates — and the biggest pain point was clear: deciding which file to keep.

Dup 2.1 fixes that, and adds several features that make finding duplicates faster and smarter.

Smart Auto-Keep

When Dup finds a group of duplicate photos or videos, you used to pick which ones to delete yourself. That's fine for a few files, but when you have hundreds of duplicate groups, it gets tedious fast.

Smart Auto-Keep does the thinking for you. It looks at each duplicate group and automatically marks the lower-quality versions for deletion, keeping the best one. It considers:

• Resolution — the highest resolution file wins
• File size — larger files typically mean better quality
• Date — originals are usually older than copies
• Photo quality score — sharper, better-exposed photos are preferred

You still review everything before deleting — Auto-Keep just pre-selects so you can scan through and confirm instead of deciding from scratch.

Cross-Format Matching

Your iPhone shoots in HEIC. When you share a photo via Messages or email, macOS converts it to JPG. Now you have two copies of the same photo — one HEIC, one JPG — and most duplicate finders treat them as completely different files.

Dup 2.1 finds these cross-format duplicates automatically. It works for both photos and videos:

• HEIC originals and their JPG exports
• MOV recordings and their MP4 conversions
• RAW files alongside their processed JPG versions

Cross-format pairs are tagged with a badge in the results, so you can see exactly why Dup matched them.

Photo Quality Ratings

Not all duplicates are equal. One might be sharp and well-lit. Another might be blurry or underexposed. Dup 2.1 analyzes each photo and gives it a quality score based on:

• Sharpness — is the photo in focus?
• Exposure — is it too dark or washed out?
• Resolution — higher resolution means more detail

When Smart Auto-Keep picks which file to keep, it uses these quality scores to make better decisions. You can also see the scores yourself when comparing duplicates side by side.

Faster Scanning

Large photo libraries — 50,000+ photos — used to take a while to scan because Dup compared every photo against every other photo. That's a lot of comparisons.

Dup 2.1 groups photos by date before comparing them. Photos taken months apart are unlikely to be duplicates, so Dup skips those comparisons entirely. The result: scanning large libraries is significantly faster, especially when your photos span several years.

Improved Face Detection

The "Remove Someone" feature from Dup 2.0 got a meaningful upgrade. Face detection is now more accurate at identifying the same person across different photos and videos, and it runs faster — especially on libraries with thousands of faces.

Bug Fixes and Polish

This release also includes dozens of bug fixes and small improvements across the scan, results, and settings screens. External drive scanning is more reliable, license validation is smoother, and the overall interface feels more polished.

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Dup is free on the Mac App Store. The free version finds all duplicates and lets you clean up to 250 MB. Pro unlocks unlimited cleanup, Smart Auto-Keep, cross-format matching, and photo quality ratings.