Compress BMP Images
BMP stores nearly every pixel literally, so a 1920×1080 screenshot takes about 6 MB. PNG keeps exactly the same pixels with lossless compression, usually at a fraction of that size, and opens everywhere a BMP does. For photographs, switch Save as to JPG or WebP to shrink them further.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
BMP expected · other image formats also work
How to use Compress BMP
- 1
Drop your images, choose files, or paste from the clipboard.
- 2
Adjust the options. The preview updates as you change them.
- 3
Click Compress. Files are processed on your device.
- 4
Download each result or everything as a ZIP.
Why use Aback Images for compress bmp
Best-in-class encoders
MozJPEG for JPG, OxiPNG and palette quantisation for PNG, libwebp and libavif for WebP and AVIF, all compiled to WebAssembly.
Live before/after
See the result and its file size on your actual image before processing the batch.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
Never bigger than the original
If compression cannot beat your file, the original is returned unchanged with a note.
Related tools
Convert BMP to PNG in your browser, ready for screenshots, logos, graphics and anything that needs transparency. Batch, private, no uploads.
Convert BMP to JPG in your browser, with transparency filled in a colour you pick. Batch, private, no uploads.
Cut PNG size by up to 80% with smart palette reduction and OxiPNG lossless optimisation, keeping transparency.
Shrink JPG, PNG, WebP, AVIF and GIF files with MozJPEG, OxiPNG and modern codecs, with a live before/after preview.
Make JPEG photos smaller with MozJPEG, the encoder that beats standard JPEG by 10-15% at the same quality.
Re-encode WebP images smaller with libwebp's best settings, including animated WebP.
Shrink animated GIFs by reducing colours, dropping frames and resizing, while keeping the animation.
Hit a file-size limit for forms and uploads. Searches quality, then dimensions, and can pad up to a minimum.
Frequently asked questions
Why not keep it as BMP?
BMP has no useful compression for full-colour images: its run-length modes only apply to 4 and 8-bit palettes. A smaller BMP is not possible without reducing colours, so PNG is the practical lossless choice.
Will software that needs BMP open the PNG?
Not always. Embedded displays and some legacy programs only read BMP; keep the originals for those and use PNG everywhere else.
Are my images uploaded anywhere?
No. Processing happens inside your browser with WebAssembly and Web Workers. The site only downloads the app code and codecs; your files never leave your device. You can confirm this with the live upload counter on the tool, or in your browser's network panel.
Can I process many files at once?
Yes. Drop a whole selection or folder. Files are processed in parallel on several worker threads, each result can be downloaded on its own, and everything can be saved as one ZIP.
Is it free? Is there a file limit or watermark?
It is free with no account, no watermark and no daily limit. The only limit is your device's memory: very large images (over roughly 100 megapixels) may be refused to keep the tab from crashing.