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Reference Formats

BMP

An uncompressed (or lightly RLE-compressed) Windows-native raster format with no meaningful metadata support, retained mainly for legacy compatibility.

Extension

.bmp

Full name

Windows Bitmap (Device-Independent Bitmap)

Introduced

1987 (Windows 2.0 original header); formalized with BITMAPINFOHEADER in Windows 3.0, 1990

Vendor

Microsoft Corporation (co-developed with IBM for OS/2)

What is inside the container

BMP is stored uncompressed by default, with optional 4-bit or 8-bit RLE compression available only for palette (indexed) images; 16-, 24-, and 32-bit true-color images are always uncompressed or bitfield-encoded. It supports 1, 4, 8, 16, 24, and 32 bits per pixel. There is no EXIF, IPTC, or XMP support at all; ICC profile embedding exists only in the rarely-used BITMAPV5HEADER variant, and ExifTool lists BMP as read-only for metadata, confirming it cannot meaningfully carry DAM metadata.

How to open it

macOS Preview (native)
Windows Photos app and Paint (native, built into GDI since Windows 3.0)
Web browsers All major browsers render BMP natively via
Cross-platform GIMP, Photoshop, IrfanView, ImageMagick all read/write BMP

For archives

Do not use as a DAM master or preservation format. Uncompressed BMP wastes storage with no compensating benefit — no meaningful metadata capacity and essentially no color-management adoption in practice. Convert incoming BMPs to TIFF (lossless, with real metadata support) on ingest.

BMP solved a narrow, early problem: Microsoft and IBM needed a simple, guaranteed-decodable raster format baked directly into the Windows GDI and OS/2 Presentation Manager, so any application could read and write bitmaps without licensing a codec. The original 12-byte header shipped with Windows 2.0 in 1987 and was reused in OS/2 1.1 the following year; the larger BITMAPINFOHEADER most BMP files use today — with 16/32-bit color and optional RLE compression — arrived with Windows 3.0 in 1990.

BMP predates every modern metadata standard — EXIF didn’t exist until 1994, XMP until 2001 — which is exactly why it never gained real support for either. In a DAM, BMP typically appears only as a legacy ingest artifact: old scans, screen captures, or output from older scientific or industrial imaging equipment. Thumbnailing is trivial since there’s no compression to decode, but there is effectively nothing to extract from the file itself for search indexing.

The practical DAM policy is straightforward: normalize any incoming BMP to TIFF or PNG immediately on ingest. This both shrinks the file (BMP’s default uncompressed storage is wasteful) and gives the asset a real chance at carrying metadata going forward, since BMP’s rare ICC-capable header variant (BITMAPV5HEADER) is almost never actually used by the software producing BMP files in the wild.

Frequently asked

Should a DAM use BMP as a master or preservation format?

No. BMP is stored uncompressed by default (RLE compression applies only to indexed palette images), so master files consume far more storage than a lossless alternative for no real benefit. It carries no EXIF, IPTC, or XMP metadata, ICC profile embedding exists only in the rarely-used BITMAPV5HEADER variant, and ExifTool treats BMP as read-only. Convert incoming BMPs to TIFF on ingest, which is lossless and supports real embedded metadata.

Does BMP support EXIF, IPTC, or XMP metadata?

No. There is no EXIF, IPTC, or XMP support at all in BMP; ICC profile embedding exists only in the rarely-used BITMAPV5HEADER variant, and ExifTool lists BMP as read-only, confirming it cannot meaningfully carry DAM metadata.

Why does BMP lack modern metadata support?

BMP predates every modern metadata standard. Its original 12-byte header shipped with Windows 2.0 in 1987, and the BITMAPINFOHEADER most files use today arrived with Windows 3.0 in 1990 — years before EXIF existed in 1994 or XMP in 2001. Microsoft and IBM designed BMP as a simple, guaranteed-decodable raster format baked into Windows GDI and OS/2 Presentation Manager, not as an asset-management format, so there was never a reason to retrofit a metadata layer once EXIF and XMP arrived.

Is a BMP file compressed?

BMP is stored uncompressed by default. Optional 4-bit or 8-bit RLE compression is available only for palette (indexed) images; 16-, 24-, and 32-bit true-color images are always uncompressed or bitfield-encoded.

Where does BMP typically show up in a DAM today?

Almost always as a legacy ingest artifact rather than a format anyone deliberately chooses — old scans, screen captures, or output from older scientific or industrial imaging equipment that saved directly to BMP. Because BMP is uncompressed, generating a thumbnail is trivial, since there's no codec to decode. But there is effectively nothing embedded in the file itself for a DAM's search index to extract, so it arrives metadata-blank and needs immediate normalization on ingest.

What bit depths does BMP support?

BMP supports 1, 4, 8, 16, 24, and 32 bits per pixel. The 1-, 4-, and 8-bit depths use an indexed color palette, and only these palette variants can carry optional 4-bit or 8-bit RLE compression. The 16-, 24-, and 32-bit depths store true color directly per pixel and are always uncompressed or bitfield-encoded — there's no RLE option once you move past indexed color.

What's the recommended DAM ingest policy for BMP files?

Normalize any incoming BMP to TIFF or PNG immediately on ingest, rather than storing it as-is. This has two benefits: it shrinks the file, since BMP's default storage is uncompressed, and it gives the asset a real chance at carrying metadata going forward, since even BMP's ICC-capable header variant, BITMAPV5HEADER, is almost never actually used by the software that produces BMP files in practice. For preservation masters specifically, prefer TIFF over PNG.

Is BMP widely compatible across platforms?

Yes. Native support has been built into Windows GDI since Windows 3.0, so Windows' own Photos app and Paint open BMP without any extra software, and macOS Preview opens it natively too. All major web browsers render BMP directly, no plugin required. Cross-platform editing and conversion tools — GIMP, Photoshop, IrfanView, and ImageMagick — all read and write BMP, which is why it remains a safe universal fallback for exchanging raster images.

Sources