Upload a photo and line up two guides with the top of the head and the tip of the chin; the crop then follows the head-height ratio your chosen spec requires. It covers Korean passport/ID (35×45), US passport and visa (51×51), European ICAO, Japanese, Chinese and Indian passports and a 30×40 résumé size, and it exports a 300 dpi file plus a 4×6 or A4 print sheet. Everything happens in your browser.
A spec fixes more than the photo size: it also fixes how much of the frame the head should fill. A photo at the right size with a face that is too small or too large still gets rejected, so the crop here is calculated from the head-height ratio rather than the frame alone.
No — it only crops. Automatic background removal leaves ragged edges around hair, which is itself a rejection reason. Shooting against a plain, light wall is far more reliable.
Eight 35×45 mm photos fit a 4×6 inch sheet. It varies with the spec and paper, and the count is shown on screen.
A small source has to be enlarged to reach the spec size, which softens it. A warning appears whenever the result is being upscaled — try a larger original. Any recent phone camera is more than enough.
Most countries follow the ICAO standard of 35×45 mm, but the US and India, among others, use a 2×2 inch (51×51 mm) square. Head-size requirements differ slightly too, so changing the spec changes the crop.