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BMP vs ICO

BMP vs ICO

A detailed comparison of BMP Image and ICO Icon — file size, quality, compatibility, and which format to choose for your workflow.

Convert BMP → ICO Convert ICO → BMP
BMP

BMP Image

Raster & Vector Images

BMP is an uncompressed raster image format native to Windows. Files are large but preserve exact pixel data with no compression artifacts. Rarely used on the web due to file size.

About BMP files
ICO

ICO Icon

Raster & Vector Images

ICO is the icon file format used for favicons and Windows application icons. A single ICO file can contain multiple image sizes and color depths for different display contexts.

About ICO files

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.

ICO Strengths

  • Multi-resolution: one file, many sizes, OS picks the right one.
  • Universal favicon support in every browser since IE5.
  • Supports transparency (1-bit since 1985, full alpha since XP).
  • Tiny file size — an entire favicon pack typically fits in under 15 KB.
  • No licensing or patent concerns — fully in the public domain spec-wise.

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.

ICO Limitations

  • Cannot compress continuous-tone images efficiently — use PNG or WebP for photos.
  • Format is essentially frozen in 1999 — no HDR, no wide gamut, no modern features.
  • Maximum image dimension is 256×256 px (inside an ICO container).
  • Editing requires specialized tools — most image editors treat it as a curiosity.

Technical Specifications

Specification BMP ICO
MIME type image/bmp image/vnd.microsoft.icon
Extensions .bmp, .dib —
Compression None (typical); RLE 4/8 bit (rare) Uncompressed bitmap or embedded PNG (Vista+)
Color depths 1, 4, 8, 16, 24, 32 bits per pixel 1, 4, 8, 24, 32 bits per pixel
Byte order Little-endian —
Max resolutions per file — 65 535 images
Max single image size — 256×256 px

Typical File Sizes

BMP

  • Small icon (32×32) 4 KB
  • Screenshot (1920×1080) ~6 MB
  • 4K image (3840×2160) ~25 MB
  • Scanned A4 at 300 dpi ~25 MB

ICO

  • Classic favicon (16×16 only) < 2 KB
  • Multi-size favicon pack (16/32/48/256) 5-15 KB
  • Full Windows app icon set 20-100 KB

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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.

BMP (Bitmap) is a raster image formato developed by Microsoft para Windows. It stores images com no compressão by default, resulting in large tamanho do arquivos mas pixel-perfect quality. It has been part of Windows since version 1.0.

BMP files open in Windows Paint, Photos, macOS Preview, GIMP, Photoshop, and virtually any image viewer. All Windows applications support BMP natively.

BMP arquivos abrir in Windows Paint, Photos, macOS Preview, GIMP, Photoshop, e virtually any image viewer. All Windows aplicativos support BMP natively.

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.

PNG is melhor que BMP in almost every scenario since it fornece sem perdas compressão (smaller files), transparência support, e wider cross-platform use. BMP is mainly relevant para legacy Windows aplicativos.