What is a BMP file?
BMP, short for bitmap, has been part of Windows since its early days. Microsoft Paint saved images as BMP by default for many years, and some scanners, lab devices and older programs still export it.
Most BMP files store each pixel as raw color values with no compression, so file size grows directly with image size. A full HD screenshot saved as a 24 bit BMP takes about 6 MB, while a JPG of the same picture is usually a small fraction of that.
BMP to JPG or BMP to PNG?
JPG is the best choice for photos, scans and artwork, where it gives the smallest files. PNG is better for screenshots, diagrams and anything with small text, because it is lossless and keeps edges sharp. Both are far smaller than BMP.
| Content | Recommended |
|---|---|
| Photo, scan, painting | JPG |
| Screenshot with text | PNG |
| Icon or logo | PNG |
Want PNG instead? Use the image to PNG converter. Not sure? Convert one file to both formats and compare the look and the size.
Where BMP files still turn up
You may find BMP files on old backup drives, in exports from industrial or medical equipment, in retro games and in screenshots from legacy software. Email services and websites often reject them, and a few of them can fill an attachment limit on their own.
Converting to JPG fixes both problems, and the new files take far less room on your drive or in cloud storage. If a result still needs to be smaller for a strict upload limit, use Compress JPG after converting.
Before converting a whole archive, open a few files to check they look right. Very old BMP files sometimes use a 256 color palette, which already limits quality. JPG keeps what is there but cannot add detail that was never stored.