Drop in a head-and-shoulders photo. Castwright crops and scales it to the exact official size for your country, enforcing the head height and eye line, then hands you the single photo and a printable sheet. Free, nothing uploaded.
Drag the top of head (including hair), the eye line, the chin and the centre line. Every measurement below is worked out from these four, so a careful ten seconds here is the whole job. The purple rectangle is what gets kept.
A pharmacy or photo shop charges around 15 dollars for two prints, and the paid apps charge a few dollars per photo or push a subscription. The actual work is arithmetic: every authority publishes a photo size in millimetres, a head height from chin to the top of the hair, and usually a range for how far the eyes must sit from an edge. This page does that arithmetic from four lines you place on your own photo, then crops and scales to the published range. Place the lines accurately and the numbers under your photo are the numbers your printed photo will measure.
The United States and India use a square 2 by 2 inch photo. The United Kingdom, the Schengen area, Australia, Pakistan and most other countries use 35 by 45 mm. Canada uses a taller 50 by 70 mm photo, and Chinese visas use 33 by 48 mm. The size on its own is not enough, which is why so many home-made photos get rejected: a 35 by 45 mm crop with the head at half the frame fails, because the head has to measure 29 to 34 mm for a British passport. The readout under your photo shows the real millimetre figures so you can see it pass before you print.
Background replacement here is a colour based cut-out that runs entirely in your browser. Against a plain, evenly lit wall it produces a clean white or light grey background in one click. Against a bookshelf, a patterned curtain or a wall the same colour as your jumper, it will not, and no amount of slider fiddling will save it. In that case the better move is to retake the photo facing a blank wall with light coming from in front of you, then use Keep original and let this tool do the crop. A visibly hacked-out background is a common reason for rejection, so a real plain wall behind you is the safest thing you can do, though the decision is still the authority's.
The sheet is laid out at 300 DPI with thin cut guides and prints on standard 4 by 6 inch photo paper, 5 by 7, A4 or US Letter. The one thing that ruins a print is the printer dialog: turn off any fit to page, scale to fit or borderless scaling and print at 100 percent, or every photo comes out a few millimetres small. The PDF is the safest option because it carries the physical page size with it.
Your photo is decoded, measured, cropped and encoded inside your browser. It is never sent to a server, which matters more than usual for a photo of your face attached to an identity document.