How the check works
Everything happens in your browser, on your own device. Here is what it measures and where each number comes from.
Nothing leaves your device
When you choose a photo, your browser opens it and measures it. The only file the page downloads is the face detector itself, from this site. The site tells your browser to refuse connections to any other address, so the photo could not be sent elsewhere even by mistake. Close the page and nothing is left.
Finding your face
The check uses YuNet, a small open face detector (MIT licence), run by a few hundred lines of code in your browser. It finds where faces are. It does not recognise who you are, and it guesses nothing about age, gender, mood or looks.
Sharpness
The check makes a grey copy of the photo half as big and back again, and measures how much changes. A photo with real fine detail changes; one that was enlarged before, or is out of focus, hardly does. When the whole photo is soft but your face is large enough, it measures your face alone, because a blurred background is fine. It also compares the file's size with its pixels: a photo stored in very few bytes was compressed hard, as chats do. Photos under 900 pixels on the long side are called small. These are the same measurements and limits Dewshot uses before a retouch.
Face size
A face under 200 pixels wide is called small: there is little detail in it to show when someone opens the photo.
Light
The check compares the brightness of your face with the rest of the photo, the left half of your face with the right, and counts pixels that are nearly white or nearly black. It is a rough reading of brightness and shadow, not of taste.
Round crop
Most apps cut the middle square out of a photo and show it as a circle. The check works out whether your face lies inside that circle and how much of its width it fills. Under 22% is called too small to recognise when shown small, over 80% too tight. These two numbers are our own rule of thumb. The square crop you can save puts your face a little above the middle, filling a little under half the width, and is made on your device.
What it will never do
- Upload your photo, or keep it.
- Give your face a score, or say whether you look attractive, young or professional.
- Use cookies, trackers or advertising.
Who makes it
This check is made by Dewshot, a natural photo retouch. Dewshot runs the same sharpness and size measurements before it retouches a photo, and this site lets anyone use them for free.