What is BMP?
BMP (Bitmap Image File) is Microsoft's native image format from the late 1980s. It stores pixel data directly, typically without compression — every pixel is written raw to disk.
Technical Characteristics
- No compression (default): raw pixel data
- Color depth options: 1, 4, 8, 16, 24, or 32 bits per pixel
- File size is linear: 1920x1080 at 24-bit = exactly ~6 MB
- Windows GDI native: perfect integration with Windows graphics APIs
- No metadata: no EXIF, no ICC color profiles
Advantages
- Zero decode time: raw pixel reads map directly to memory
- Absolutely lossless: no algorithm touches the pixel values
- Simple to implement: trivial to parse in embedded systems and game engines
- Legacy compatibility: universal support in Windows tools from any era
Size Comparison (1920x1080 photographic image)
| Format | Size |
|---|---|
| BMP (24-bit) | ~6 MB |
| TIFF (uncompressed) | ~6 MB |
| PNG (lossless) | ~2-3 MB |
| JPEG (quality 85) | ~400-800 KB |
| WebP (quality 85) | ~250-500 KB |
When BMP Makes Sense
- Processing images in Windows where decode speed > file size
- Working with Windows GDI or DirectX at low level
- Exchanging graphics with embedded systems lacking PNG/JPG decoders
- Legacy print workflows requiring BMP input
Don't use BMP for: web publishing, email, storing photographs, any situation where file size matters.
Converting BMP
# FFmpeg: BMP to PNG (lossless)
for f in *.bmp; do ffmpeg -i "$f" "${f%.bmp}.png"; done
# ImageMagick
convert image.bmp -quality 92 image.jpg
mogrify -format png *.bmp
In modern projects, PNG replaces BMP entirely: same lossless quality, 3-5x smaller files, universal support with full alpha transparency.
Advanced Use Cases
Web optimization at scale: e-commerce sites with thousands of products can reduce bandwidth costs 60-80% by migrating from JPG to AVIF or WebP. Cloudflare Images, Imgix and Cloudinary offer on-the-fly transformation based on client Accept header — serving AVIF to modern Chrome/Edge, WebP to Safari/Firefox, JPG fallback to legacy browsers. Print-ready output: converting RGB to CMYK with ICC profile (US Web Coated SWOP v2 for commercial offset, FOGRA39 for European) ensures printed colors match preview on calibrated screen. PDF/X-1a and X-4 are formats required by professional printers. Professional photography: Adobe workflow consists of RAW (camera input) → DNG (archival) → PSD (non-destructive editing) → TIFF (deliverable) → JPG/WebP (web/social). Each stage preserves different capabilities. Vector graphics: SVG is preferred for logos, icons, flat illustrations — scales infinitely without loss and animates with CSS/JavaScript. For modern UIs, icon fonts (Font Awesome) are being replaced by SVG sprites for better accessibility and customization.
Best Practices and Professional Tips
Format selection by content: photographs → JPG (quality 85-95) or WebP (quality 80-90); graphics with text/fine lines → PNG or WebP lossless; flat illustrations → SVG; UI icons → SVG; screenshots → PNG; HDR → AVIF or JPEG XL. Color profile management: always embed ICC profile in professional files (Adobe RGB for pre-press photography, sRGB for web, Display P3 for Apple ecosystem). Without embedded profile, viewers assume sRGB which can cause visible color shifts. Resolution vs size: for web display, 72 DPI is sufficient; for professional print, 300 DPI minimum. Lazy loading + responsive images: combine <img loading="lazy" srcset> with AVIF/WebP fallback chain for bandwidth savings without sacrificing UX. Metadata privacy: smartphone JPG files contain GPS, camera model, exact date — use exiftool -all= to strip before uploading to social networks if privacy matters.
Compatibility and Technical Considerations
KaijuConverter supports more than 30 image formats (JPG, PNG, WebP, AVIF, HEIC/HEIF, GIF, BMP, TIFF, SVG, ICO, PSD, RAW from multiple vendors, JPEG XL) using ImageMagick 7.x, libvips, and format-specific libraries (libpng, libjpeg-turbo, libwebp, libavif, librsvg). We process images up to 100 MB with resolutions up to 16384×16384 pixels and depths of 8/10/12/16-bit per channel. EXIF and metadata: we read all embedded information (camera, lens, GPS, capture data, ICC profile) and migrate it to output when destination format supports it — critical for professional workflows that depend on provenance tracking. HDR: we support PQ and HLG transfer functions for AVIF/JPEG XL/HEIC HDR (rec.2020 color space). Performance: a typical 5 MB JPG→WebP conversion takes 1-3 seconds; iPhone 12 Mpix HEIC→JPG takes 2-5 seconds; multi-layer PSD→PNG flat may require 5-15 seconds depending on complexity. Privacy: TLS 1.3 encryption, isolated Docker containers, automatic deletion after 2 hours with multi-pass overwrite.
Related conversions
Most teams that read this guide convert images in one of these directions: