Having cataloged 530+ photo specifications across 175+ countries while building our tool Passport Size Photo, here are the rejection reasons we see most often — and how each one can be checked programmatically before an application ever reaches a consular officer.

1. Head size out of range

Almost every country defines head height as a fraction of total photo height — typically 50–70%. ICAO's baseline puts the head at 70–80% of the frame; the US wants 1–1⅜ inch (25–35 mm) from chin to crown. A photo that looks perfectly fine to a human eye is often 10% outside spec.

Programmatic check: run face landmark detection, compute the head bounding box, and compare the ratio against the target country's range.

2. Wrong background

The US and China require plain white or off-white; many EU states accept light grey; the UK wants plain light grey or cream. Shadows, gradients, and patterned walls are instant rejections.

Programmatic check: sample the border region of the photo and measure luminance variance — anything above a small threshold means the background isn't uniform enough.

3. Pose and expression

Neutral expression, mouth closed, both eyes open, facing the camera straight on. A visible smile is grounds for rejection in most official contexts, and tilted heads throw off every downstream measurement.

4. Glasses

Glare on lenses, tinted lenses, or frames covering the eyes are common reject triggers — the US has disallowed glasses entirely in passport photos since 2016.

Programmatic check: detect specular highlights in the eye region; if the eye cannot be localized cleanly, flag the photo.

5. Resolution and compression

Print applications typically want 300–600 DPI at the specified physical size. An over-compressed JPEG introduces artifacts that governments' own scanners reject. A 2-megapixel selfie upscaled to passport size fails the DPI check.

Programmatic check: compute effective DPI from pixel dimensions versus required print size, and reject anything below spec.

6. Eye position and centering

The US expects eyes to sit 1⅛–1⅜ inch (29–35 mm) from the bottom edge. Head centered too high or too low fails even when head size is correct.

Programmatic check: locate pupils, then verify their vertical position against the country's allowed band.

7. Head coverings and accessories

Allowed only for documented religious or medical reasons, and the full face must remain visible from hairline to chin. Hats for fashion are out everywhere.

8. Photo age

Most countries require the photo to be taken within the last 6 months. Software can't verify capture date — but it can remind you how old your source photo is and warn before you reuse one from two years ago.

The takeaway

None of these checks require subjective judgment — they're all ratios, thresholds, and pixel measurements. That's exactly the kind of problem software is good at, and exactly why "close enough" photos keep failing: humans eyeball it, governments measure it.

That's also the premise behind Passport Size Photo — it looks up the exact spec for the document you're applying for (530+ specs, 175+ countries and document types), crops your photo to the correct ratio, and runs compliance checks on head size, background, and eye position, then outputs print-ready files at 300 or 600 DPI. Better to fail a free automated check than a paid government one.