LinuxWhat is the PNT file format?
The .pnt file stores a MacPaint bitmap image, a format developed by Bill Atkinson at Apple Computer and bundled with the original Apple Macintosh 128K at launch in January 1984. It is one of the earliest consumer-grade bitmap paint formats ever released.
Every .pnt file has a fixed canvas of 576×720 pixels at a color depth of 1 bit per pixel - strictly black and white, with no grayscale or color. This unusually tall canvas was deliberate: the original Mac's 9-inch screen displayed only 512×342 pixels, and MacPaint allowed the user to scroll around the larger working area. File size hovers close to 53 KB in all cases because the canvas dimensions are fixed; PackBits run-length encoding compresses solid areas efficiently, so simple images are considerably smaller on disk.
The file structure consists of a 512-byte header - a version field at offset 0 (usually 00 00 00 00) followed by 38 brush pattern entries - then PackBits-compressed pixel rows at 72 bytes × 720 rows. On the original Macintosh, HFS identified MacPaint documents by the type code PNTG and creator code MPNT rather than by file extension. Files extracted from old Mac disk images sometimes carry a 128-byte MacBinary wrapper prepended to this header.
MacPaint was discontinued around the System 7 era, eventually superseded by TIFF and BMP for bitmap editing. Apple donated the MacPaint source code to the Computer History Museum in 2010. Today, tools such as IrfanView, XnView MP, and GraphicConverter can still open legacy .pnt files.
Security & safety
RISK: LOWMacPaint is a simple, fixed-structure legacy bitmap format with no scripting or embedded content. The only risk is in the parsing of old binary format data; no known exploits exist for modern viewers.
Format details
in a nutshell- Microsoft PowerPoint Legacy Template (Mac) - Old Macintosh PowerPoint versions used .pnt for presentation templates; rare and obsolete.
Programs that open PNT files
Windows3 apps
macOS2 apps
GraphicConverter
Paid File > Open - GraphicConverter has comprehensive legacy Mac format support including MacPaint/PNTG. 
Technical details
deep spec| Encoding | Binary |
| Byte order | Big-endian (Motorola 68000) |
| Color depth | 1 bpp - monochrome (black and white only; no grayscale or color) |
| Fixed canvas | 576 × 720 pixels (all MacPaint files share this exact canvas; no other sizes exist) |
| Resolution | 72 dpi - matched the original Mac 9-inch 512 × 342 display |
| Compression | PackBits RLE (Apple run-length encoding), applied row by row |
| File structure | 512-byte header (4-byte version field + 304-byte brush pattern array + padding) followed by PackBits-compressed pixel rows: 72 bytes × 720 rows |
| Typical file size | 5-53 KB (canvas is fixed; solid areas compress well; complex dithered images approach the ~53 KB maximum) |
| Version field | 4-byte field at offset 0: typically `00 00 00 00` (version 0) or `00 00 00 02` (version 2) |
| HFS identification | Type code `PNTG`, creator code `MPNT` (original Macintosh HFS - no file extension required on classic Mac OS) |
| MacBinary wrapper | Files from old Mac disk images may carry a 128-byte MacBinary header prepended, extending total file size |
| MIME type | image/x-macpaint |
| Released | January 1984 (Mac 128K, Apple Macintosh launch) |
| Latest version | Single historical version (format unchanged from 1984) |
| Open standard | Yes · royalty-free |
| Specification | leopard-adc.pepas.com |
PNT conversions
Community Q&A
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