How to resize a photo to 3.5 cm × 4.5 cm
- Tap Choose your photo and pick the picture you want at passport size.
- Leave DPI at 300 unless your form named a different number.
- Tap Resize to 3.5 × 4.5 cm and check the pixel size shown on the result.
- Save the file, and keep the original in case a different form wants another size.
Why the same size gives different pixel counts
Centimetres describe paper. Pixels describe files. The number that converts one into the other is DPI — dots per inch — and a form that asks for 3.5 by 4.5 cm without naming a DPI has left out a third of the instruction. At 300 DPI you get 413 by 531 pixels; at 200 DPI the same physical size is 276 by 354; at 600 it is 827 by 1063. All three are correct 3.5 by 4.5 cm photographs.
If your form quoted both a physical size and a pixel size, divide to find the DPI they meant and type that in. If it quoted only centimetres, 300 is the safe answer and the one a print shop will assume.
This page does not keep your photo’s shape, on purpose
Most photographs are not 3.5 by 4.5. Forcing a 4:3 phone photo into that rectangle stretches a face slightly, which is why every other control on this site defends the shape and this one does not: you asked for an exact rectangle and an exact rectangle is what the form will measure.
If the stretch is visible, crop the photo to roughly 7:9 first and then come back. Cropping decides what stays in frame, which is a judgement only you can make; resizing then costs nothing.
When the form also caps the file size
Plenty of portals want 3.5 by 4.5 cm *and* under 50 KB, which is two requirements that pull against each other. Set the size here first, and if the result is over the cap, run it through the 50 KB page afterwards — that page will spend quality rather than pixels, so the grid you just set survives.