Select a folder to scan. Supports images (JPG, PNG, GIF, WebP) and videos (MP4, WebM, MOV).
Everything you need to know about finding and cleaning up duplicate files with the Color Signature algorithm. Scroll down for step-by-step instructions, tips, and answers to common questions.
Sakarto looks inside your images and videos to detect duplicates — not just files with the same name. It creates a visual "fingerprint" for each file and groups ones that look alike, even if they were resized, re-saved in a different format, or had minor edits applied.
Finds copies regardless of file name, resolution, format, or light editing.
Extracts frames from video files and compares their visual content.
Groups appear in real time as the scan runs — no waiting for it to finish.
For JPEG files, reads the embedded thumbnail instead of the full image — 5–10× faster.
The Color Signature algorithm analyzes the actual color content of each image rather than comparing pixels directly. Here's what happens step by step:
Each image is drawn onto a 288×288 pixel canvas (or a tiny JPEG thumbnail in Fast Mode). This makes all images comparable regardless of their original size.
The canvas is divided into a 24×24 grid of overlapping 3×3 cell neighborhoods. Each neighborhood produces averaged color values in Y, U, V channels (brightness separated from color — the same system used in digital video).
The YUV values across all regions are normalized per channel, producing a compact color "signature" for the image. Two images with the same overall color distribution — even at different resolutions or quality settings — will produce very similar signatures.
Signatures are compared using squared Euclidean distance. If the distance between two signatures falls below the threshold, the files are grouped as duplicates. An aspect-ratio pre-check filters out pairs with very different proportions before comparison.
All image fingerprinting runs in a background Web Worker via OffscreenCanvas — your browser tab stays fully responsive during scanning. Video processing runs on the main thread and pauses if you switch tabs.
Click 📁 Select Folder to Scan to open a native folder picker (Chrome / Edge). Or drag and drop a folder onto the page. In Firefox or Safari, use the file input fallback.
A progress bar shows how many files have been processed. Duplicate groups appear live as they're found — you can start reviewing before the scan finishes. You can switch browser tabs freely during image scanning (videos pause when the tab is hidden and resume when you return).
Results are shown in numbered groups. Each group contains files that look similar to each other.
Ctrl+Click two or more cards, then click ⚖️ Compare in the toolbar. A modal opens showing each file with full metadata, a similarity percentage, and action buttons. For 3+ files, a full pairwise similarity matrix is shown.
Select files and use the toolbar buttons. With Queue Mode on (recommended), files are staged for review first:
When Queue Mode is enabled (the default), clicking Move or Delete stages files in a queue instead of acting immediately. Switch to the Move Queue or Delete Queue tab in the sidebar to review what's staged, remove individual files, then execute when ready.
With Queue Mode disabled, a confirmation dialog appears and the operation runs immediately after you confirm.
| Button / Action | What it does |
|---|---|
| 🔄 New Search | Reload the page and start a fresh scan |
| 📋 Copy (N) | Copy selected filenames to clipboard. N = count selected. |
| 📂 Move (N) | Move selected files or stage them in the Move Queue |
| 🗑️ Delete (N) | Delete selected files or stage them in the Delete Queue |
| ✕ Deselect All | Remove selection from all cards |
| ⚖️ Compare (N) | Open the compare modal for Ctrl+clicked files. Needs 2+. |
| 🔇 Videos | Toggle mute/unmute for all video cards |
| Queue Mode checkbox | When checked: stage files for review before executing. Recommended. |
| Fast Mode checkbox | Use EXIF thumbnail for JPEG scanning — much faster. On by default. |
| Click card | Select / deselect the file |
| Ctrl + Click card | Add / remove from compare list (purple border) |
| Click & drag (empty area) | Box-select multiple cards at once |
| Ctrl + drag | Add to existing selection with box |
| Right-click card | Context menu: Copy / Move / Delete / Compare |
| 🔍 hover icon | Open full-size preview with metadata and action buttons |
| Hover video card | Auto-play the video clip |
"Color Signature caught every re-uploaded Instagram photo in my folder. 4,200 files scanned in under 2 minutes with Fast Mode on."
"I had hundreds of social media downloads — same photo at different qualities. Color Signature grouped them all perfectly. Nothing else I tried came close."
"The YUV approach is brilliant for colour-based matching. Found 340 duplicates in a holiday photo collection I thought was clean."
"Queue Mode + Color Signature = no accidents. I've been using it weekly to clean my downloads folder. The browser-based approach is exactly what I needed."
Always back up your files before deleting anything. Deleted files bypass the recycle bin and cannot be recovered.
For very large collections, scan one subfolder at a time. The tool works best with up to 5,000–10,000 files at once.
Click the 🔍 icon to view files full-size. Use Compare to see them side-by-side. Keep the largest file size — it usually means better quality.
Use Move instead of Delete if you're unsure. You can always permanently delete from the destination folder later.
Fast Mode reads the embedded thumbnail rather than the full image. Almost always produces the same results at a fraction of the scan time.
Color Signature works well for most photos. If you're missing rotated or cropped copies, try ORB. For large folders where speed matters, try aHash or BlockHash.
Browsers cannot silently read your disk — a folder picker dialog is required every time you scan.
The File System Access API bypasses the OS recycle bin. Deleted files are gone permanently. Use Queue Mode to review before executing.
You can't compare files across two separate folders in one scan. Workaround: scan their common parent directory.
50,000+ images may slow down or crash the tab on devices with less than 8GB RAM. Split large folders into smaller batches.
Browsers throttle background video decoding. The scanner pauses video processing when the tab is hidden and resumes automatically when you return. Image scanning is unaffected.
Move and Delete require Chrome 86+ or Edge 86+ (File System Access API). Firefox and Safari can scan and display results but cannot move or delete files. Use "Download List" to export results in those browsers.
remove() method permanently deletes files without going through the OS Recycle Bin or Trash. Queue Mode is on by default to prevent accidents — it stages files for review before any deletion is executed. Use the full-size preview and Compare modal to verify groups, and consider using Move to a "Sakarto-Duplicates" folder rather than deleting outright, at least until you're confident in the results.