Find copies without risking originals
How to find duplicate images online
- 1
Select images from the folders you want to compare
Choose exports, downloads, screenshots or photo batches together. File paths are not exposed to the page.
- 2
Set how similar a match must be
Use strict mode for obvious copies, balanced mode for resized exports or burst mode for broader visual review.
- 3
Review exact and visual evidence
Each group shows similarity, format, dimensions, file size and the reason Rantey recommends one keeper.
- 4
Download a cleanup plan
Verify the CSV in your own file manager. Rantey never deletes, moves or modifies the selected files.
More than matching filenames
Exact duplicates and visual duplicates are different
Two files can display the same photograph while having different names, metadata, dimensions, formats or compression bytes. Rantey first calculates SHA-256 to prove byte-identical matches. It then compares normalized luminance structure, edge direction and color distribution to find likely visual copies. Orientation variants help surface quarter-turn rotations and horizontal flips.
What this duplicate image finder can detect
| Match type | How it is detected | Review advice |
|---|---|---|
| Exact duplicate | Same SHA-256 fingerprint across every file byte | Still check filenames and folder purpose |
| Renamed copy | Exact bytes with a different visible filename | Usually the safest cleanup candidate |
| Resized export | Similar normalized visual structure at another resolution | Keep the resolution needed for future work |
| Recompressed copy | Strong perceptual match with different bytes or file size | Inspect quality before choosing the larger file |
| Format conversion | Visual match across JPG, PNG and WebP | Consider transparency and lossless needs |
| Rotated or flipped copy | Best match occurs against an orientation variant | Confirm that orientation is not intentional |
| Burst or near-duplicate | Lower-threshold visual similarity | Compare expression, focus and timing manually |
Why Rantey does not delete files automatically
A lower-resolution image may contain edits, metadata or a crop you intentionally need. A larger file is not always the best composition, and two burst photos can look similar while capturing different moments. Browser security also prevents a normal webpage from silently reorganizing your library. The exported cleanup plan records recommendations for review; deletion remains a deliberate action in your operating system.
Privacy and performance on phones
Photos are decoded one at a time into small analysis canvases. SHA-256 and visual fingerprints stay in the current browser tab, and pair comparisons use those compact fingerprints instead of repeatedly decoding full images. This limits memory use, but a large 300 MB collection can still take time on an older phone. Keep the tab open until the progress bar finishes.
Frequently asked questions
Duplicate image finder FAQ
How can I find duplicate images online?+
Choose a set of JPG, PNG or WebP images. Rantey calculates a SHA-256 fingerprint for exact files and visual fingerprints for resized, recompressed, rotated or flipped copies, then groups likely duplicates locally in your browser.
Are my photos uploaded to a server?+
No. File hashing, image decoding, visual comparison, grouping and report creation happen inside your browser. Rantey does not receive your selected images.
What is the difference between an exact and visual duplicate?+
Exact duplicates contain identical file bytes and share the same SHA-256 hash. Visual duplicates can look the same while using another filename, format, resolution or compression setting.
Can it find resized or recompressed copies?+
Yes. Perceptual fingerprints compare the visible image structure rather than relying only on names, sizes or file bytes. The similarity threshold controls how strict the grouping should be.
Can it find rotated and flipped images?+
The comparison checks orientation variants of the normalized visual fingerprint, including quarter-turn rotations and a horizontal flip. Heavily cropped or substantially edited photos may not match.
Does the tool delete duplicate photos?+
No. A website should not silently delete personal files. Rantey recommends a keeper, estimates reclaimable space and exports a CSV review plan so you can verify and remove files safely in your own file manager.
How does Rantey choose the recommended keeper?+
The recommendation favors higher pixel dimensions, stronger sampled edge detail and less lossy formats. It is only a review aid; metadata, edits and personal preference may make another copy more valuable.
How many images can I compare?+
You can compare up to 80 JPG, PNG or WebP images with a combined source size of 300 MB. Processing is sequential and yields between files to remain usable on phones.