Sources & Verification 3 of 8
Technical Specifications
The following specifications were checked against the W3C PNG Specification, Third Edition. They describe the format, not a universal production preset.
| Claim | Verified specification |
|---|---|
| Image model | PNG stores raster images; every PNG contains a static image, and an APNG may also contain animation frames |
| Color types | Grayscale, truecolor RGB, indexed color, grayscale with alpha, and truecolor RGB with alpha |
| Bit depths | Depending on color type: 1, 2, 4, 8, or 16 bits per sample |
| Compression | Compression method 0 uses DEFLATE in a zlib datastream and preserves decoded sample values losslessly |
| Transparency | Supported through alpha-bearing color types or the tRNS chunk where permitted |
| Color information | PNG can carry standardized color-space and profile information, including sRGB and ICC profile data |
| Physical pixel metadata | The optional pHYs chunk records pixel density or aspect ratio; it does not create image detail |
| Dimensions | Width and height are stored as unsigned integers limited by the specification to values no greater than 2,147,483,647; software and hardware limits are normally far smaller |
| Integrity checking | The PNG signature and chunk CRCs support file identification and transmission-error detection |
| CMYK | PNG does not define a standard CMYK image color type |