ID photo online

ID photo online: resize for documents and enrollment forms

Public service exam forms, government portal registrations and selection processes often require photos with specific dimensions — most commonly 3×4 cm or ICAO standard passport photo (35×45 mm). Pixel dimensions depend on the required resolution (DPI): at 300 DPI, a 3×4 cm photo needs 354×472 px. This tool offers ready presets for the most common Brazilian document formats.

Drag an image here or click to selectJPG, PNG, WebP, GIF, BMP — up to 50 MB

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Dimensions and resolution for document photos

DPI (dots per inch) defines print density. 300 DPI is the standard for photographic quality printing. To convert centimeters to pixels: width_px = (width_cm / 2.54) × DPI. Example: 3 cm = (3 / 2.54) × 300 = 354 px. This tool's presets already apply this calculation.
The ICAO standard for passports requires: 35×45 mm (413×531 px at 300 DPI), face centered between 70–80% of the photo height, white or off-white background, no glasses, no hat, neutral expression, uniform lighting. The tool resizes to the correct dimensions — the other requirements depend on the original photo.
Many portals specify a kilobyte limit in addition to dimensions. A 3×4 photo at 300 DPI in JPEG at 80% typically lands between 20–60 KB — within any reasonable limit. If the portal requires PNG, the file may be 3–5x larger; prefer JPEG when accepted.

Size conversion for document photos

3×4 cm photo (300 DPI)

Input: Selfie 12 MP (4032×3024 px)
Expected output: 354×472 px (preset disponível)

Use the Presets tab > Documents > "3×4 Photo" to apply automatically.

ICAO Passport 35×45 mm (300 DPI)

Input: Foto frontal com fundo branco
Expected output: 413×531 px (preset disponível)

Check issuing authority requirements — dimensions are standardized but variations exist.

5×7 cm photo (300 DPI)

Input: Foto horizontal de câmera
Expected output: 591×827 px (preset disponível)

Common format for home printing and photo albums.

Full tool FAQ

What is the difference between resizing and cropping an image?

Resizing changes the dimensions of the entire image — it becomes larger or smaller, but the content is preserved in full (possibly distorted if the aspect ratio changes). Cropping selects a specific region and eliminates the rest — the resulting dimensions are exactly those of the selected area.

What happens when I disable the aspect ratio lock and only change the width?

What are the correct dimensions for an Instagram feed post?

What resolution should I use for documents like ID photos or passport pictures?

Why should a YouTube thumbnail be 1280×720 px?

Does the processed image lose quality each time it is resized?

What is interpolation and how does it affect quality when enlarging an image?

Can I use this tool to prepare images for printing?

Frequently asked questions

Can I use this tool for passport photos?

For resizing to correct dimensions, yes. For the photo to be officially accepted, beyond dimensions, there are specific requirements about background, expression, lighting and face positioning that depend on the original photo. Always check the issuing authority requirements (Federal Police for Brazilian passports) before submitting.

Why did the exam portal reject my photo even at the correct dimensions?

Beyond dimensions, portals check: file size in KB (your file may exceed the limit); file format (may require JPEG only); specific metadata or color profile; and sometimes perform automatic face verification. If dimensions are correct, check the KB size limit and try JPEG at 80% if you are uploading PNG.