Choosing the Celebrities
The list starts from Wikidata: every living person covered by at least ten language editions of Wikipedia. Each is ranked by how many people read their English Wikipedia article over the previous six months, with a boost for being covered in many languages, so the list reflects who is famous now. Because English Wikipedia under-counts stars from other regions, a second list ranks people from East and South Asia, Southeast Asia, Latin America, Africa and the Middle East by views on their own languages' Wikipedias, about half of them women.
Only adults are included, and a known birth date is required, so nobody under 18 slips in. People known mainly for adult entertainment or for serious crimes are left out.
Only Freely Licensed Photos
Every photo comes from Wikimedia Commons and must carry a free license that allows reuse with credit: public domain, CC0, CC BY, CC BY-SA and a few similar licenses. Photos under non-commercial or no-derivatives licenses are never used, and files flagged for deletion are skipped.
For each photo Ollie keeps the photographer's name, the license and a link to the original, and shows that credit under the photo in your results.
Checking Every Photo
Candidates come from the person's own Wikidata photo, photos tagged as depicting them, their Commons category, and name searches. Each one is checked automatically before it is kept: one clear, large face; not a group shot; facing the camera; sharp; in colour, so no black-and-white or sepia prints; no sunglasses; an adult face; and a real photograph rather than a statue, wax figure, drawing, poster or meme, checked with both the file's title and an image model.
Identity is checked too. A face-recognition model compares every candidate with the person's own Wikidata photo and with their other photos, and keeps only clear matches. If the reference photos disagree about who the person is, the person is skipped rather than guessed. Near-duplicates and too many photos from the same event are dropped.
Building the Index
Each celebrity ends up with 2 to 12 verified photos. Every photo is run through Ollie's network once, and the resulting fingerprints are stored side by side, one per photo rather than one averaged fingerprint per person, so a search can show you the exact photo that matched you best.
When you search, your fingerprint is compared with every stored one, and each celebrity is scored by their closest photo.