BMP to JPG — Escaping the Uncompressed Image Stone Age

I genuinely thought BMP files had gone extinct until last year, when a client sent me a folder of 347 scanned receipts — every single one a 24-bit BMP. The folder was 2.1 GB. After converting to JPG at quality 85, it was 58 MB. Same images, same visual content, 97% less disk space.

That's BMP for you.

A Quick History Lesson

Microsoft introduced the BMP format (Bitmap Image File) in 1987 alongside Windows 2.0. It was designed for one thing: storing pixel data with zero complexity. No compression algorithms, no metadata overhead, no fancy encoding. Every pixel gets its exact color values written sequentially into the file.

This made perfect sense in 1987. Memory was expensive, CPU time was precious, and decompressing an image on the fly was a luxury. BMP let the system just dump pixels straight to the display buffer. Fast, simple, dumb.

The problem is that "no compression" means absurd file sizes by modern standards.

The Numbers Don't Lie

A 1920x1080 image in 24-bit BMP: 5.93 MB. Every time. It's pure math — 1920 times 1080 times 3 bytes per pixel, plus a small header.

That same image as JPG at quality 90: typically 200-400 KB depending on content. Photos compress better; screenshots with sharp text compress less.

Some real-world comparisons I've measured:

Content Type	BMP Size	JPG (q85) Size	Reduction
Desktop screenshot (1080p)	5.93 MB	310 KB	95%
Scanned document (A4, 300dpi)	25.1 MB	890 KB	96%
Photograph (12MP camera)	36.0 MB	2.8 MB	92%
Simple diagram with flat colors	5.93 MB	85 KB	98%

There's no scenario where keeping the BMP makes sense for sharing or archiving, unless you specifically need lossless pixel-perfect data — and even then, PNG does that job in a fraction of the space.

Where BMP Files Still Lurk

You'd think nobody uses BMP in 2026. You'd be wrong. Here's where they keep showing up:

Old scanner software. Plenty of office scanners from the 2010s shipped with bundled software that defaulted to BMP output. The machines still work fine, so nobody updated the software. Legacy industrial and medical systems. I've seen manufacturing quality-control cameras that output BMP exclusively. Medical imaging workstations from the 2000s often exported to BMP when you needed to pull images out of the proprietary viewer. Windows Snipping Tool (old versions). Before Microsoft updated it, the classic Snipping Tool on Windows 7/8 saved as BMP by default unless you changed the dropdown every single time. Embedded systems and firmware. Boot splash screens, POS terminal displays, and kiosk software often use BMP because the rendering code is trivially simple — no decoder library needed. Clipboard operations. When you paste a screenshot from clipboard into certain older applications, it lands as BMP data internally.

Why JPG and Not PNG?

Fair question. If BMP is uncompressed and you want to compress it, why not use PNG (which is lossless) instead of JPG (which is lossy)?

For photographs and scans: JPG wins. The lossy compression is nearly invisible at quality 80-90, and the files are 5-10x smaller than PNG. A scanned document that's 25 MB as BMP would be about 8 MB as PNG but under 1 MB as JPG.

For screenshots, diagrams, and UI mockups: PNG is actually the better choice. These images have sharp edges, flat colors, and text — exactly what PNG's lossless compression handles well. JPG introduces visible artifacts around sharp edges.

For batch conversion of mixed content where you just need "smaller files, good enough quality": JPG at 85 is the pragmatic choice.

Desktop Conversion Tools

Paint — yes, Microsoft Paint. Open the BMP, File > Save As > JPEG. It's been doing this reliably since Windows XP. No quality slider though, so you get whatever default Paint chooses (roughly quality 75). IrfanView is the power user's choice. Open BMP, hit S to save, pick JPG, and you get a quality slider from 1-100. For batch conversion, use File > Batch Conversion — point it at a folder of BMPs and it'll churn through hundreds in seconds. Set quality to 85 and forget about it. XnConvert handles batch jobs even more elegantly, with drag-and-drop and the ability to chain operations (convert format + resize + rename in one pass).

Converting Online

When you're dealing with a handful of BMPs and don't want to install anything, MyPDF's BMP to JPG converter handles it cleanly. Drag, drop, download. It's especially useful on machines where you can't install software — work laptops with locked-down admin policies, Chromebooks, that sort of thing.

One Thing to Watch

JPG doesn't support transparency. If your BMP somehow has an alpha channel (rare, but 32-bit BMPs exist), converting to JPG will flatten it against a white background. If transparency matters, convert to PNG instead.

Related Tools

• BMP to JPG — Instant browser-based BMP conversion
• BMP to PNG — Lossless alternative when you need transparency or sharp edges
• Image Compressor — Further reduce JPG file sizes
• JPG to PDF — Bundle converted images into a document