BMP to JPG: Turn Huge Bitmaps Into Small, Shareable Photos
BMP photographs are the worst of both worlds: enormous files that also happen to be awkward to share. An uncompressed bitmap of a photo can be twenty or thirty megabytes — too big to email and rejected by many upload forms.
For photographic content, JPG is the answer. Its compression was built for exactly this kind of image, and it can shrink a BMP by 90% or more while keeping a result your eyes can't tell apart from the original. This guide walks through the trade-offs and how to get a clean conversion.
BMP to JPG
Turn bulky BMP bitmaps into small, shareable JPG photos.
How much smaller will it get?
For photographs, the reduction is dramatic — often 90–95% off an uncompressed bitmap. JPG achieves this by discarding fine detail that the human eye barely registers, spending its bytes on the edges and tones you actually notice. The busier and more photographic the image, the bigger the win.
Flat graphics and screenshots compress less impressively and can even look worse in JPG, because its compression struggles with sharp edges and text. For those, PNG is the better target.
The transparency caveat
JPG doesn't support transparency. Most BMP files are fully opaque, so this rarely matters — but if your bitmap does contain a transparent area, JPG will fill it with white. When transparency needs to survive, convert to PNG instead.
Choosing a quality setting
JPG lets you balance size against fidelity with a quality slider. For most photos, 80% keeps the image looking crisp while cutting the file size hard. Going above 85% grows the file quickly for gains few people can see; dropping below 70% starts to show blocky artefacts in skies and smooth gradients. The live preview makes it easy to find the point where the image still looks right.
A private, in-browser workflow
Uploading a thirty-megabyte bitmap to a conversion website is slow and sends your image to someone else's server. PixelResize does the whole job locally: it decodes the BMP, draws it onto a white background and encodes a JPG in your browser. Nothing is uploaded, and the small JPG downloads the moment it's ready.
Key takeaways
- Photographic BMPs typically shrink by 90% or more as JPG.
- JPG can't hold transparency — transparent areas become white.
- Around 80% quality is the sweet spot for most photos.
- For screenshots, text or graphics, PNG usually looks better than JPG.
- Converting in the browser avoids uploading a large file to a server.