Blur faces before you share.

Pixelate. A strong mosaic throws pixel information away, which makes reconstruction much harder than a soft gaussian blur. That is why it is the default here.

In Chromium-based browsers with the built-in FaceDetector, one click boxes every face it finds — and you can always add or redraw boxes by hand. In other browsers manual selection works everywhere.

No. Selection, censoring and export all happen in your browser; the photo never leaves your device. Check the network tab if you like.