What the engine is actually measuring
A face search doesn't compare pictures. It converts a face into a numerical signature built from the geometry between features — the spacing of the eyes, the position of the nose relative to the mouth, the shape of the jaw — and compares those signatures.
That single fact explains almost everything else. Anything that preserves geometry is fine, however dramatically it changes how the picture looks. Anything that alters geometry is a problem, however subtle it looks to you.
Harmless: things that only change how it looks
You can ignore all of these. They change the pixels, not the face.
- Instagram-style colour filters, black and white, heavy grading
- Compression, re-saving, screenshotting once
- Cropping and resizing (as long as the face stays big enough)
- Different lighting, different camera, different year
- Beards, haircuts, makeup, glasses that don't obscure the eyes
Harmful: things that move the features
These genuinely reduce match scores, sometimes to nothing.
- Reshaping beauty filters that slim the jaw or enlarge the eyes
- Extreme profile angles — anything past about three-quarters
- Sunglasses, masks, a hand across the face
- Motion blur, especially frames grabbed from video
- Very low resolution, where the features are a handful of pixels
- Wide-angle selfie distortion taken very close to the lens
Crop before you upload
This is the highest-value thing you can do and almost nobody does it.
If your photo is a group shot, a full-body picture or a wide scene, crop it down so the head fills most of the frame before uploading. A face occupying a small fraction of a large image may not be detected at all, and if it is, the effective resolution of the face is far lower than the file size suggests.
A 400×400 crop of just the head beats a 4000×3000 photo where the person is standing at the back.
Pulling a frame from a video
Don't screenshot a random moment. Scrub through until you find a frame where the person is facing the camera and roughly still, then crop tight.
Video frames are the single most common source of failed searches, because the frame that looks good to a human — mid-laugh, mid-gesture — is frequently motion-blurred and turned away. Pause on the dull frame, not the expressive one.
Hard limits worth knowing
Files under 1 KB are rejected before anything else happens — that usually means a thumbnail or a badly compressed screenshot. JPG, PNG and WebP are accepted, up to 10 MB.
If the image has no detectable face, you'll be told so immediately and nothing is charged. That check is free and happens before payment, which is deliberate: there is no point selling someone a search that cannot succeed.
If you have several photos, which one?
Pick the plainest. Not the most flattering, not the most recent, not the one you like best.
The ideal is boring: even light, neutral expression, facing the camera, nothing across the face, head filling the frame. A passport photo is close to the perfect input, which is also why LinkedIn headshots tend to produce the highest-scoring matches of any source.
Last updated 3 August 2026