PBM to JNG Converter
FileFlip converts PBM to JNG entirely inside your browser, using ImageMagick compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert a PBM file to JNG?#
- Drop your PBM file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to JNG and the conversion starts on its own. FileFlip downloads 14.1 MB of WebAssembly the first time and nothing after that, then runs ImageMagick on your own machine.
- Save the JNG file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting PBM to JNG lose quality?#
Yes, once. PBM keeps everything and JNG does not, so this is the first time the file meets a lossy encoder. At high quality the difference is hard to see, and it is worth keeping the PBM original, because every later re-save of the JNG loses a little more.
Is it safe to convert PBM files online?#
Yes, because nothing is uploaded. FileFlip converts PBM files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What PBM to JNG actually does to the file#
Converting PBM to JNG runs on ImageMagick, downloads 14.1 MB of WebAssembly the first time and nothing after that, encodes a lossless source with a lossy encoder for the first time.
| Engine | ImageMagick |
|---|---|
| Conversion path | One step: PBM → JNG |
| Downloaded to your browser | 14.1 MB, once, then cached by your browser |
| Quality | Lossy, first generation |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
What is a PBM file?#
A PBM file stores a strictly black-and-white, one-bit-per-pixel raster image as plain ASCII characters or packed binary bits, in the Netpbm project's Portable Bitmap format.
Use PBM for a strictly black-and-white bitmap, such as a fax page or a stencil mask, that needs to move between tools without any image library.
Convert PBM to PNG once the image needs compression or has to sit alongside greyscale or colour images in the same pipeline.
What is a JNG file?#
A JNG file holds a single still image whose colour data is compressed as baseline or progressive JPEG inside the same chunk-based container PNG uses, with an optional PNG- or JPEG-encoded alpha channel for transparency.
There's little reason to create a new JNG file today; the format only makes sense inside an existing MNG animation that already mixes JPEG and PNG frames.
Convert JNG to JPG or PNG for anything meant to display in a browser, since none of the major browsers render JNG natively.
PBM to JNG questions people ask#
What does PBM stand for?
PBM stands for Portable Bitmap, the black-and-white member of the Netpbm family of image formats that Jef Poskanzer created to move images between Unix tools. It is the strictly one-bit sibling of the colour PPM and greyscale PGM formats.
Is a 1 a black pixel or a white pixel in a PBM file?
In a PBM file, a 1 represents a black pixel and a 0 represents a white pixel, which is the opposite of what many people expect from a plain greyscale scale. This is defined directly in the Netpbm project's own PBM specification.
Why is my PBM file bigger than a similar PNG?
A PBM file stores one bit per pixel with no compression at all, while PNG compresses that same data losslessly, so a large black-and-white image can end up many times smaller as a PNG. PBM trades file size for a format simple enough to read and write without any image library.
What opens a JNG file?
JNG files open in GIMP, Gwenview and ImageMagick-based tools, but no mainstream web browser renders them. That gap is the main reason JNG never spread beyond the small set of software built around the MNG format.