Point it at a folder and it finds the duplicate and similar photos that aren't byte-identical — resized, re-saved, WhatsApp'd. All the hashing happens in this tab, and nothing is deleted unless you say so.
Choose a folder of photos. On Chrome and Edge you'll be asked for permission and can delete right here; other browsers scan and hand you a list.
Where the pile came from: my father's laptop had 41,000 photos and about 12,000 actual photographs. Every WhatsApp forward, every "let me back this up" that copied instead of moved, every export from a phone that renamed everything, all piled into one folder called Pictures (new), itself sitting inside Pictures (old). He wouldn't delete any of it because he couldn't tell which was which. The tools I found for him were downloads from sites with three buttons all called Download, and the first one I dared try wanted forty dollars to actually remove anything. His photos never needed to leave the laptop, and neither did his money. A browser can hash forty thousand images in a few minutes; the rest is a decent review screen and the discipline to never delete anything he didn't tick.
— he kept 12,400 photographs and 3 copies of a picture of a cat he doesn't know
two fingerprints, both hand-written, both on your machine
the strictness dial, explained by what it finds
what this tool will never do
the questions that come with 41,000 photos
If your browser can decode HEIC it hashes them like anything else; if not, they're skipped rather than silently mis-grouped. Converting them first (our sibling site does this on-device too) makes the whole library easier to live with anyway.
The biggest file is pre-selected because it's usually the least-compressed original — but check the dimensions on screen: a bigger file at smaller dimensions means someone saved a low-res copy at high quality, and the original is elsewhere in the group.
Yes — any folder your computer can see, including drives and network shares, as long as you can pick it in the folder dialog.
The browser removes them from the folder. Depending on your operating system they may or may not land in the recycle bin — so treat deletion as permanent, and if these are irreplaceable, have a backup first. This is stated in the confirmation dialog too.
Pick a parent folder that contains both, keep "include subfolders" ticked, and it compares everything as one pile — which is exactly how the "Pictures (new)" inside "Pictures (old)" situation gets solved.
longer reads from the light table
what changed, newest first