I made a passport photo checker that runs entirely in your browser. What would make you trust it?

Hi, I'm the maker of CropPass (croppass.com).

After getting a visa photo rejected for a slightly uneven shadow and feeling uneasy uploading my biometrics to random cloud tools, I built a local-first alternative.

You add a photo you took at home. CropPass finds your face, crops it to the size your country wants (35×45 mm for a UK passport, 2×2 in for the US) and checks head size, eye line, centring, light on your face, the background and glasses. When a check fails, it tells you what to do, for example "Face a window or a lamp so the light falls evenly on both sides of your face, with no shadows."

Everything happens on your device. Face detection runs in the browser, so the photo is never uploaded, and there's no account. For online forms it makes the file they ask for: the DS-160, for example, wants a square JPEG between 600 and 1200 px and no bigger than 240 KB.

New since I launched here on 17 October: you can add up to 6 photos, and the one that does best on the checks goes in the editor.

Pricing, so it isn't a surprise: cropping, the checks, the preview and a watermarked sample are free. A full-size download needs a pass, $4.99 for one person or $9.99 for a family. The checks are a guide; the passport office makes the final call.

20-second video: https://youtu.be/AliMkkmzD0M

Two questions for anyone who has done this themselves. What tripped you up with your passport or visa photo? And would "never uploaded" be enough for you to trust a tool with a photo of your face, or would you need something more?