PCX to QOI Converter
Convert PCX to QOI in your browser. PCX files usually come from DOS paint programs (PC Paintbrush, Deluxe Paint), old games, and fax and scanner software; QOI is the better fit for fast lossless storage in games and tools. You get a lossless RGBA QOI file. Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
PCX expected · other image formats also work
How to use PCX to QOI
- 1
Add your PCX files: drop them here, choose them, or paste from the clipboard.
- 2
There is nothing to tune: the QOI is written losslessly. Resizing and rotating are under More options if you need them.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .qoi files one at a time or together as a ZIP.
Why use Aback Images for pcx to qoi
Where the QOI goes next
QOI opens in game engines, GIMP 3, ImageMagick, XnView MP and many small libraries.
QOI next to PCX
Both sides are lossless, so the size depends on how well the QOI encoder handles this picture compared with the PCX's byte-wise run-length encoding.
Written without a lossy pass
The QOI is written losslessly, so the pixels decoded from the PCX arrive unchanged.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
PCX vs QOI
What changes from PCX to QOI
Encoding: the PCX uses byte-wise run-length encoding; QOI uses lossless, byte-aligned run, index, difference and literal codes, and the download is a lossless RGBA QOI file.
Bit depth: 1, 2, 4 or 8 bits per pixel with a palette, or 24-bit as three 8-bit planes in the PCX; QOI allows 8 bits per channel, and the QOI written here has 8 bits per channel.
Colour: a 16 or 256-colour palette, or 24-bit RGB in the PCX; QOI supports RGB or RGBA, tagged sRGB or linear, written here as 8-bit sRGB.
Metadata: the PCX can carry only a 128-byte header with the resolution; QOI can carry none: a 14-byte header holds only size, channels and colour space, but nothing is copied across.
About PCX
PCX is the image format of ZSoft's PC Paintbrush, the standard for DOS paint programs, scanners and games before GIF and BMP took over. It compresses with a simple run-length scheme.
A PCX file has a 128-byte header (the byte 0x0A, version, encoding, bits per pixel, image window, DPI, a 16-colour palette and the number of colour planes), then RLE-compressed scanlines; 256-colour files end with the byte 0x0C and a 768-byte palette.
PCX files usually come from DOS paint programs (PC Paintbrush, Deluxe Paint), old games, and fax and scanner software.
About QOI
QOI is a modern lossless format that encodes 20-50 times faster than PNG with similar file sizes. It is popular in games and tools that value speed and simplicity.
A QOI file is a 14-byte header ('qoif', width, height, channels, colour space), a stream of chunks that each encode a run, an index into 64 recently seen colours, a small difference from the previous pixel or a literal value, and an 8-byte end marker.
When converting PCX to QOI makes sense
QOI is the better choice for fast lossless storage in games and tools, while PCX suits DOS-era software, retro games and old fax or scanner tools.
QOI strengths: Extremely fast lossless encode and decode; Simple, open spec. Drawbacks to weigh: Not supported by browsers or mainstream apps.
Limitations
- DOS art was often drawn for 320×200 screens shown at 4:3, where pixels were slightly taller than wide, so it can look a little squashed on a modern display.
- A palette PCX holds at most 256 colours, so a full-colour target keeps them exactly but adds nothing.
- Browsers and most mainstream apps cannot open QOI; it is meant for games and tools that read it directly.
- QOI files are usually close to PNG in size but much faster to encode and decode.
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Frequently asked questions
Does converting PCX to QOI lose quality?
QOI is written losslessly, so the pixels are stored exactly as decoded.
Which apps open QOI files?
Game engines, GIMP 3, ImageMagick, XnView MP and many small libraries. It does not open in web browsers.
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.