BMP vs WMF
A detailed comparison of BMP Image and Windows Metafile — file size, quality, compatibility, and which format to choose for your workflow.
Technical Specifications
| Specification | .BMP | .WMF |
|---|---|---|
| MIME type | image/bmp | image/wmf |
| Extensions | .bmp, .dib | — |
| Compression | None (typical); RLE 4/8 bit (rare) | — |
| Color depths | 1, 4, 8, 16, 24, 32 bits per pixel | — |
| Byte order | Little-endian | — |
| Extension | — | .wmf |
| Container | — | Sequence of GDI drawing records |
| Successors | — | .emf (1993), .emf+ / .emfx (2000) |
| Related spec | — | [MS-WMF] (Microsoft Open Specifications) |
Strengths Comparison
.BMP Strengths
- Dead-simple format — trivially easy to read and write.
- Lossless and uncompressed — perfect bit-exact pixel storage.
- Universally supported in Windows applications since 1985.
- Supports 1, 4, 8, 16, 24, and 32-bit color depths.
.WMF Strengths
- Native Windows vector format.
- Efficient for line-art and diagrammatic images.
- Preserved in Office clipboard workflows.
Limitations
.BMP — Limitations
- Enormous file sizes — no meaningful compression in typical use.
- Not a web format — browsers support it but nobody serves BMPs over HTTP.
- No metadata support (no EXIF, no ICC profile in practice).
- Multiple header versions mean "a BMP" is ambiguous — parsers must handle several variants.
.WMF — Limitations
- Windows-only — poor Mac and Linux support.
- 2005 security vulnerability eroded trust.
- 16-bit coordinates in original WMF limit canvas size.
- Largely superseded by SVG for modern vector exchange.
- Not a web format.
Frequently Asked Questions
BMP (Bitmap) is a raster image format developed by Microsoft for Windows. It stores images with no compression by default, resulting in large file sizes but pixel-perfect quality. It has been part of Windows since version 1.0.
WMF (Windows Metafile) is an image format used to store raster graphics — a two-dimensional grid of pixels describing a picture. It is part of the raster & vector images family and designed around a specific trade-off between file size, visual fidelity, and feature support (transparency, colour depth, compression type). Photographers, web designers, and content creators choose WMF when its particular strengths match the publishing target.
BMP files open in Windows Paint, Photos, macOS Preview, GIMP, Photoshop, and virtually any image viewer. All Windows applications support BMP natively.
Most desktop photo viewers (Windows Photos, macOS Preview, GIMP, Photoshop, Affinity Photo) open WMF natively. On mobile, iOS Photos and Google Photos display WMF in the gallery when supported by the OS. If the format is rare or new, convert to JPG or PNG first — both are universally readable — using our WMF to JPG or WMF to PNG converter.
PNG is better than BMP in almost every scenario since it provides lossless compression (smaller files), transparency support, and wider cross-platform use. BMP is mainly relevant for legacy Windows applications.
Upload the WMF to KaijuConverter and pick a target format (JPG, PNG, WebP, HEIC, TIFF, BMP, SVG, PDF). The conversion runs in the browser via ImageMagick and returns a download in seconds. No account or installation required; both input and output delete automatically within two hours.
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