FormatDrop
Image Format

BMP

Bitmap Image File

BMP is Windows's original image format — uncompressed, simple, and enormous. It predates the web, digital cameras, and virtually every modern image format. Today BMP appears mainly from Windows screenshot tools, old painting software, and certain hardware devices. If you have a BMP file, converting to JPG or PNG gives you the same image in a fraction of the file size.

What is BMP?

BMP (Bitmap Image File, also called Device Independent Bitmap or DIB) was introduced with Microsoft Windows 1.0 in 1985 as the native image format for the Windows GDI (Graphics Device Interface). The format stores pixel colour values in a straightforward grid — by default with no compression at all. A 1000×1000 pixel BMP at 24-bit colour occupies 3 MB (3 bytes per pixel × 1,000,000 pixels). The same image as JPG at quality 90 would be 50–200 KB, and as PNG would be 200 KB–1 MB. BMP does support some compression schemes (RLE — Run-Length Encoding, which works well for images with large flat-colour areas) but virtually all BMP files in the wild use no compression. The format supports bit depths from 1-bit (monochrome) to 32-bit (with alpha channel), though 24-bit (8 bits per channel, no alpha) is most common. BMP files are still generated by: Windows Snipping Tool and PrintScreen (in older Windows versions), MS Paint when saving as BMP, FAX machines and document scanners on legacy software, certain industrial cameras and machine vision systems, and embedded systems that need a simple image format without a complex encoder.

BMP pros and cons

Advantages

  • Trivially simple format — every piece of software ever made can read BMP
  • No encoding or decoding complexity — raw pixel data
  • Lossless quality (uncompressed)
  • No proprietary codec or licensing required

Limitations

  • Enormous file sizes — 5–50× larger than equivalent JPG or PNG
  • Not suitable for web use (browsers load it, but it's wasteful)
  • No modern web browser displays BMP inline efficiently
  • Lacks advanced features: no transparency support in 24-bit mode, no metadata standards
  • Essentially obsolete — PNG is lossless, smaller, and universally supported

When should you convert BMP files?

Convert BMP to JPG to share photos via email or web — the file size reduction is dramatic (typically 95%+ smaller for photographic content). Convert BMP to PNG if you need lossless quality with a smaller file — PNG lossless compression reduces BMP size by 50–90% without any quality loss. Convert BMP to WebP for web use — WebP lossless is even smaller than PNG.

Convert BMP files

JPG→PNG

All FormatDrop conversions run entirely in your browser — no file upload, no server processing. Your files stay on your device.

BMP FAQ

Why is my BMP file so large?
BMP stores raw pixel data with no compression by default. Every pixel takes 3 bytes (24-bit colour) — so a 1000×1000 pixel image is exactly 3,000,000 bytes (about 3 MB) regardless of whether the image is mostly one solid colour or a complex photograph. Other formats use compression: JPG discards imperceptible detail, PNG uses lossless DEFLATE compression. Converting to PNG gives you lossless quality at 50–90% smaller sizes.
Does Windows still use BMP?
Less than it used to. Windows 10 and 11 still support BMP in applications like MS Paint (which now defaults to PNG), and the system wallpaper engine supports BMP. But the default capture format for Windows screenshots changed from BMP to PNG in Windows Vista. Modern Windows applications generally default to PNG or JPG. BMP persists mainly in legacy software and specialized hardware.

More formats

HEICWebPAVIFEPUBWebMOpusMP3WAVM4AFLACAACMP4AVIMKVMOVJPGPNGGIFSVGTIFFICOEPSARWOGGWMVPPTXPagesPDFDOCXRAWHEVCH.264AIFFM4VWMA3GPDNGRTFPSDOGVTSFLVAIXLSXCSVZIPAPNGMIDIJPEG XLMPG/MPEGVOBM2TSAC3ALACDTSJP2HEIFAPECBZ3G2SRTDOCPPTXLSODTODSM3URAR7ZM4BAMRTXTMOBITARGZJSONXMLYAMLKEYMTSCR2NEFMXFTGACAFASSVTTDSFRMF4VWVASFRMVBORFRW2EAC-3TTAISODMGXZDjVuFB2AUM4RAZW3MKAEXRVCFICSAAXPRCMP2SPXXSPFM3U8