filetity

PNG or JPG -> BMP · Local tool

PNG to BMP

Turn a PNG or JPG into an uncompressed BMP, for software that wants one.

Last updated

  1. 01 / Your device

    the file stays here

  2. 02 / Browser memory

    the work runs locally

  3. 03 / Back to you

    saved on this device

When you would use this

Situations, not settings.

A machine that only reads BMP
Label printers, industrial panels and lab instruments often support one raster format, and it is this one.
An old Windows application that rejects PNG
Software written before PNG was common still opens a BMP without complaint.
A tool that wants raw pixels with no decoding
BMP stores pixels uncompressed, so anything reading it needs no codec at all, which is sometimes the whole requirement.

How it works / no cloud

A conversion engine, not an upload form.

No browser can write a BMP, so filetity writes the container here: a 14 byte file header, a 40 byte BITMAPINFOHEADER, then 24 bit pixels stored bottom up in BGR order with every row padded to a multiple of four bytes. That is the plain shape every reader accepts, which matters because the software asking for a BMP is usually the software that chokes on anything fancier.

  • Offline ready
  • Installable app
  • No file limit queue

Straight answers

No accordion. Nothing hidden.

Is it free?
Yes, with no watermark and no page limit.
Does it need an account?
No. There is no account system.
Is my file processed on my device?
Yes. The file is read by your browser and never uploaded. There is no server to send it to.
What formats are supported?
PNG and JPG in. BMP out, 24 bit and uncompressed, one file per image or a ZIP when you convert several.
What are the limits?
A 24 bit BMP has no alpha channel, so transparent areas are filled with white rather than kept. The file is uncompressed by definition: a 1920 by 1080 image is about 6 MB whatever it contains. There is no 32 bit or compressed variant here, because the readers that need BMP are the ones least likely to accept either.
Does it work on mobile?
Yes, on any modern mobile browser. Large files are limited by the memory the phone gives the browser.
Does it work offline?
Yes. Nothing is downloaded to make this work, so it keeps working with no network connection once the page has loaded.
Does JPG to BMP work here too?
Yes, the page takes both. JPG to BMP and PNG to BMP follow the same path: decode with the browser's own codec, draw on a canvas, write the BMP container. A JPG has no transparency to lose, so the only change is that the file gets much larger, because BMP stores every pixel in full.
Why is the BMP so much bigger?
Because BMP does not compress. Three bytes per pixel, always, whatever the picture is. A 1920 by 1080 image is about 6 MB as a BMP whether it is a photograph or a blank white rectangle. PNG and JPG both compress, which is why they replaced it everywhere that has a choice.
What happens to transparency?
It is filled with white. A 24 bit BMP has no alpha channel at all, so something has to go behind the transparent pixels, and white is the safe default: leaving them as they are would write black. If the transparency matters, PNG is the format that keeps it.
Why would anything still want a BMP?
Because it is the simplest raster format there is, so it is what old and embedded software supports when it supports only one thing. Industrial panels, label printers, some medical and scientific instruments, a few Windows applications from the 1990s that are still running. Nobody chooses BMP; something else insists on it.

Keep working locally

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