JNG to SIXEL Converter
FileFlip converts JNG to SIXEL 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 JNG file to SIXEL?#
- Drop your JNG 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 SIXEL 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 SIXEL file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting JNG to SIXEL lose quality?#
SIXEL is a lossless format, so nothing further is lost here, but nothing is recovered either. Whatever the JNG encoder already threw away is gone, and the SIXEL file will usually be several times larger for exactly the same content.
Is it safe to convert JNG files online?#
Yes, because nothing is uploaded. FileFlip converts JNG 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 JNG to SIXEL actually does to the file#
Converting JNG to SIXEL runs on ImageMagick, downloads 14.1 MB of WebAssembly the first time and nothing after that, writes a lossless file that cannot recover what the source already discarded, and drops transparency.
| Engine | ImageMagick |
|---|---|
| Conversion path | One step: JNG → SIXEL |
| Downloaded to your browser | 14.1 MB, once, then cached by your browser |
| Quality | Lossless output, but nothing is recovered |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
What survives the conversion
| What is in the file | This conversion | Why |
|---|---|---|
| Transparency | Dropped | The target format has nowhere to put it. |
Worth knowing before you start:
- the target holds at most 256 colours, so a full-colour image is quantised to a palette
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.
What is a SIXEL file?#
A SIXEL file holds a bitmap encoded entirely as printable ASCII characters, using DEC's six-pixel-tall encoding scheme, so it can be sent to a printer or terminal over a plain 7-bit serial link and displayed without any separate image protocol.
Use Sixel when an image needs to display inline inside a terminal session, such as showing a chart or a thumbnail over SSH without opening a separate viewer.
Convert a Sixel image to PNG once it needs to be viewed anywhere outside a terminal emulator that understands the encoding.
JNG to SIXEL questions people ask#
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.
Is JNG the same thing as PNG?
No. A JNG file reuses PNG's chunk-based container but compresses its colour data as JPEG instead of PNG's lossless method, so it behaves more like a JPEG with an optional transparency layer than a true PNG. JNG exists specifically as the lossy, photographic sibling inside the MNG animation format.
Why did JNG never catch on?
JNG's fate was tied to MNG, the animated format it was built to complement, and MNG never got the browser support GIF and later APNG had. Combined with newer formats like WebP and JPEG XL covering the same lossy-plus-transparency need, JNG stayed a niche format used mainly by MNG-aware software.
What is a SIXEL file?
A SIXEL file is a bitmap image encoded as printable ASCII text using DEC's six-pixel-tall scheme, originally built in the early 1980s so DEC printers and terminals could receive graphics over the same serial link used for plain text.