ID Photo Size Guide: What 1-Inch and 2-Inch Really Mean, Plus Exam Registration Scenarios
More people ask than you'd think
"What size is a 1-inch photo?" — ID photo dimensions are an evergreen Chinese search topic, because the answer is scattered across three layers: print sizes in millimeters, pixel requirements from upload systems, and per-exam background rules. This guide aligns all three at once.
The base conversion table
| Spec | Print size | Common pixels (300dpi) | Typical use |
|---|---|---|---|
| 1-inch | 25×35mm | 295×413 | Resumes, work IDs, most exams including CET |
| 2-inch | 35×49mm | 413×579 | Diplomas, marriage certificates, some visas |
| Small 1-inch | 22×32mm | 260×378 | Driver's license, ID card (some regions) |
| Large 1-inch | 33×48mm | 390×567 | Graduation certificates, bar exam, some civil-service posts |
| ID card | 26×32mm | 358×441 | Resident ID application |
Pixels are 300dpi print-standard conversions; if the upload system specifies its own numbers (e.g. "at least 295×413"), the system wins.
Background conventions: white, blue, red
- White: the mainstream for identity documents — ID cards, passports, visas, postgraduate-exam online confirmation
- Blue: education-related — diplomas, degrees, CET, teaching-certification review
- Red: medical insurance and senior cards in some regions (varies locally; follow the local requirement)
Exams diverge often: postgraduate online confirmation in recent years asks for white backgrounds; teaching certification has shifted to white in some provinces at the review stage — the upload page's own instructions always outrank any reference table, this one included.
High-frequency registration scenarios
| Scenario | Common requirement |
|---|---|
| Postgraduate exam (online confirmation) | White-background digital JPG; exact pixels/size per the local admission notice (commonly ≥295×413) |
| CET-4/6 | 1-inch, mostly blue |
| Teaching certification | 1-inch white or blue (registration and final review may differ) |
| Civil service | 1-inch, blue or white per the recruitment notice |
| Social security card | 1- or 2-inch white, varies by region |
| Visas | Country-specific: US 51×51mm, Japan 45×45mm, Schengen 35×45mm — check the spec reference per country |
Workflow from phone photo to compliant ID picture
- Shoot: plain wall, face the camera, even light, no hats or accessories — original quality caps every later step.
- Crop: the ID photo resizer with a preset (e.g. 1-inch 295×413) and drag-to-position face guides.
- Swap background (when needed): the background tool replaces the wall with standard blue/red; hair edges are the hard part, zoom in and inspect.
- Verify: the compliance checker validates size, ratio and file size against the target spec.
- Print layout (for paper): the print layout tool tiles 1-inch photos onto 6-inch paper for the print shop.
Implementer's note
The 18 specs in the reference table share one data source with the resizer tool (PHOTO_SIZES, single source of truth) — the crop box and the table can never disagree; that constraint was set at design time. Pixel math is uniformly 300dpi, and upload minimums are "≥" checks: generate at high resolution and let the system compress, never scale up — interpolated softness shows worst along face edges.