What is the PAINT file format?
A .paint file (also stored as .mac or .pntg) is a MacPaint bitmap image produced by Apple's original MacPaint application, released on January 24, 1984 alongside the first Macintosh computer. Written by Bill Atkinson, MacPaint was one of the first mass-market paint programs and helped popularize the WYSIWYG desktop metaphor.
Every .paint file stores a fixed canvas of exactly 576 × 720 pixels at 72 dpi - the printable area of an Apple ImageWriter - in 1-bit monochrome (black and white only). Pixel rows are compressed row-by-row using PackBits run-length encoding, an Apple ROM routine, keeping files compact: typical size is around 10 KB despite the uncompressed pixel data requiring 51,840 bytes.
A file may begin with an optional 128-byte MacBinary header (Mac type code PNTG, creator MPNT) followed by a 512-byte document header reserved for pattern data. Alternatively, the 512-byte header begins immediately at offset 0 when no MacBinary wrapper is present. No single fixed magic byte sequence covers all variants.
MacPaint 2.0 (1988) added color tools to the application but left the document format unchanged - all .paint files remain 1-bit. The format was superseded by PICT on classic Mac, and later by PNG and TIFF for archival purposes. MacPaint was discontinued when Mac OS X arrived in 2001. Modern tools such as GIMP, XnView, and ImageMagick can still open these historically significant files.
Security & safety
RISK: LOWHistorical raster image format; no executable code, scripting, or active content. Safe to open in any compatible viewer.
Format details
in a nutshell- macOS / iOS Drawboard Paint - Some paint-style apps on macOS/iOS may save files with .paint extension in their own formats, unrelated to the 1984 PNTG format.
Programs that open PAINT files
Windows3 apps
macOS3 apps
MacPaint (historical)
Free Original Apple application; requires classic Mac OS emulator (BasiliskII, Mini vMac). Discontinued 1998. 
Linux2 apps
Technical details
deep spec| File type | Fixed-size monochrome bitmap (raster) |
| Color depth | 1 bpp (black and white only) |
| Canvas dimensions | Fixed 576 × 720 pixels |
| Resolution | 72 dpi (matches Apple ImageWriter printable area of 8 × 10 inches) |
| Compression | PackBits run-length encoding, applied per scan line |
| Uncompressed pixel data | 51,840 bytes (576 × 720 ÷ 8) |
| Typical file size | ~10 KB (highly compressible monochrome) |
| Header structure | Optional 128-byte MacBinary wrapper + 512-byte document header (pattern data, reserved space) |
| MacBinary type/creator codes | PNTG / MPNT |
| Byte order | Big-endian (Motorola 68000 architecture) |
| Encoding | Binary |
| MIME type | image/x-macpaint |
| Associated OS | Classic Mac OS (System 1-9) |
| Successor formats | PICT (.pct) for Mac graphics; PNG and TIFF for modern archival use |
| Released | January 24, 1984 (Macintosh launch; MacPaint 1.0) |
| Latest version | MacPaint 2.0 (1988) - format unchanged |
| Open standard | Yes · royalty-free |
| Specification | www.fileformat.info |
PAINT conversions
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