Why the head height matters more than the photo size
Almost everyone gets the outer dimensions right — they are printed on the form. The head height is where photos are refused, because it is a narrower range than people expect and there is nothing on a camera that tells you when you have hit it.
HM Passport Office asks for 29 to 34 mm, crown to chin inside a 35 × 45 mm frame. That is a specific proportion of the picture, and it is why this tool asks you to mark the crown and the chin rather than simply cropping to the right rectangle: without those two points there is no way to measure the thing being specified.
Mark them, and the readout tells you the head height in millimetres and whether it falls inside the published range. If it does not, the fix is nearly always to retake the photo from a different distance rather than to crop harder — enlarging a small head produces a soft picture that fails on resolution instead.
Printed at true size, or a digital file
The online service takes a digital photo — at least 600 × 750 px and between 50 KB and 10 MB. A paper application needs two identical printed 35 × 45 mm photos.
For a print, the sheet is laid out at real physical size with the resolution written into the file, so “print at 100%, no scaling” means something at the shop counter. A photo printed at the wrong scale is one of the most common reasons for a rejection, and it is entirely invisible on screen.
For a digital submission, the pixel dimensions and the file-size limits are set for you. A photo that is too large is rejected by the upload form rather than by a person, which at least tells you straight away.
Nothing here is uploaded
A passport photo is a picture of your face, cropped to a specification that says which country's document you are applying for, produced on the day you applied. That is a great deal to hand to a free website with an advertising business model.
Everything on this page runs in your browser. There is no upload, no queue, no temporary file on somebody's server that gets cleaned up “within 24 hours”, and no third-party request of any kind — not even a font. You can verify that in your browser's network tab rather than taking it on trust.
If the background needs flattening, that runs locally too, on a photo that has not gone anywhere.
Sources
- UK — Digital pixel minimum, file size, photo age, expression, glasses
- GOV.UK — Get a passport photo. https://www.gov.uk/photos-for-passports checked 2026-08-25
- UK — Printed size 35 × 45 mm, head 29–34 mm, cream or light grey background
- GOV.UK — Photo requirements for printed photos. https://www.gov.uk/photos-for-passports/photo-requirements checked 2026-08-25