What BMP is — and why it's so big
BMP (bitmap) is a Windows image format from the early days of the PC era. Its hallmark: it usually stores pixels completely uncompressed — every pixel is written out individually, with no space saving at all. That makes BMP files enormous: a simple screenshot as BMP can weigh many megabytes, while the same image as PNG or JPG needs only a fraction. For web, sending, and storage, BMP is therefore almost always the wrong choice.
Which format to convert to?
The format choice follows the same old logic (see JPG vs PNG):
- Photo → JPG or WebP: small, ideal for the web.
- Screenshot, graphic, text, transparency → PNG or lossless WebP: sharp and lossless.
- Keep the BMP → only if an old program or a special device explicitly requires it.
Because BMP is uncompressed, every conversion is a win: several megabytes often become a few hundred kilobytes, with PNG even without any quality loss.
How to convert — browser-local
Browsers can display BMP and re-encode it via the Canvas API. Drag the BMP file into the image converter, choose JPG, PNG, or WebP as the target, and download the result — the file isn't uploaded. Especially with old BMP scans (documents, IDs, receipts) still sitting on some hard drive, the browser-local route is the safe one: the personal content never leaves your device.
After converting: don't forget to shrink
A BMP can be at a very high resolution. If the converted image will be shared or uploaded, it's worth resizing it to a sensible size afterward and compressing it — then the unwieldy ancient format has become a handy, modern image.
In short
- BMP = uncompressed = huge. Almost never the right choice.
- Photo → JPG/WebP, graphic → PNG/WebP.
- Converting always helps — every alternative is smaller.
- Browser-local for sensitive scan content.