Pixel dimensions explained: minimums, maximums and exact sizes
Digital photo rules state pixel sizes three different ways: a minimum you must clear, a range you must land in, or one exact size you must hit. Reading the rule the wrong way produces files that are technically big enough and still refused. This guide explains the three patterns, why upscaling a small photo never satisfies a minimum, and where the exact-size portals hide. For the arithmetic that connects pixels to millimetres, see the mm to pixels guide.
Minimums: a floor, not a target
gov.uk wants at least 600 x 750 pixels for the UK digital photo, and Ireland wants at least 715 x 951 for Passport Online. A minimum is about information: the authority needs enough real detail to measure a face. That is why we render the UK file at 900 x 1125, comfortably above the floor, and why a floor cannot be met by enlarging a small image. Upscaling invents pixels by interpolation; the file's dimensions grow but its detail does not, and quality checks built to catch blur and compression treat the result the way the US renewal treats a scanned print for MyTravelGov: as a photo that is not an original camera image.
Ranges: land inside, aim at the recommendation
Some portals publish a window. Korea's online re-issue accepts 395 to 431 pixels wide by 507 to 550 high and recommends 413 x 531 for the Korean passport; the US visa systems accept 600 x 600 up to 1200 x 1200 for the DS-160 photo. When a recommendation exists inside the range, use it, because it is usually the size the portal's own processing assumes. Our spec data stores a minimum and a target for every digital document, and a maximum where the authority sets one; the file we export is always the target.
Exact sizes: no tolerance at all
A few portals accept one size and nothing else. Finland's police application wants exactly 500 x 653 pixels for the Finnish passport, with deviations as small as one pixel refused, and the DV lottery entry wants exactly 600 x 600. Exact sizes come from the portal's software, not from any print dimension, so you cannot derive them from millimetres and DPI; they have to be read from the rule. This pattern is the easiest to fail by hand, because most photo editors resize to 'about' a size when the aspect ratio of the crop does not match; check the saved file's properties, not the editor's input box.
Megapixels are not dimensions
Camera marketing counts total pixels; the rules count width and height separately, plus their ratio. A 12-megapixel photo in the wrong orientation can still fail a 600 x 750 minimum on one axis after cropping, and a file can clear both minimums while being the wrong shape, which is its own rejection; the aspect ratio guide covers that failure. The practical order is: crop to the document's shape first, then confirm the resulting width and height against the rule, then worry about kilobytes last.
Frequently asked questions
My photo is 4000 x 3000. Why did the portal say it is too small?
Landscape orientation. After cropping to a portrait document shape, the usable width came from the photo's height-side pixels, and the crop fell under the minimum on one axis. Shoot in portrait or stand further back.
Can I upscale an old photo to meet a minimum?
The upload may go through, but the detail the minimum exists to guarantee is not there, and quality and compression checks are built to notice. Authorities that address it directly, like the US online renewal, require an original camera image rather than a scan or re-processed copy.
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We are an independent service, not a government website. Applying for a passport or visa is done with your government; we only prepare the photo.