JPG to QOI Converter
Convert JPG to QOI in your browser. JPG files usually come from cameras, phones, scanners and almost every app that saves photos; 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
JPG expected · other image formats also work
How to use JPG to QOI
- 1
Add your JPG 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 jpg to qoi
Where the QOI goes next
QOI opens in game engines, GIMP 3, ImageMagick, XnView MP and many small libraries.
QOI next to JPG
The QOI keeps the decoded pixels without lossy compression, so expect it to be larger than the JPG.
No new artefacts
JPG is already lossy, since it stores lossy DCT coding in 8×8 pixel blocks, with colour usually stored at half resolution; the QOI keeps the decoded pixels losslessly, so this step adds no compression damage of its own.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
JPG vs QOI
What changes from JPG to QOI
Encoding: the JPG uses lossy DCT coding in 8×8 pixel blocks, with colour usually stored at half resolution; QOI uses lossless, byte-aligned run, index, difference and literal codes, and the download is a lossless RGBA QOI file.
Bit depth: 8 bits per channel in the JPG; QOI allows 8 bits per channel, and the QOI written here has 8 bits per channel.
Colour: YCbCr shown as RGB, greyscale, or CMYK from print software in the JPG; QOI supports RGB or RGBA, tagged sRGB or linear, written here as 8-bit sRGB.
Metadata: the JPG can carry EXIF (camera, date, GPS), XMP, IPTC and an ICC profile in APP segments; QOI can carry none: a 14-byte header holds only size, channels and colour space, but nothing is copied across.
About JPG
JPEG is the universal photo format. It compresses by discarding fine detail the eye is least sensitive to, which makes photos small but blurs sharp edges and text if pushed too far.
A JPEG starts with the bytes FF D8 and is a run of marker segments: APP1 carries EXIF and often a thumbnail, APP2 an ICC profile, DQT the quantization tables that decide the quality, and SOS the compressed scan, which ends at FF D9.
JPG files usually come from cameras, phones, scanners and almost every app that saves photos.
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 JPG to QOI makes sense
QOI is the better choice for fast lossless storage in games and tools, while JPG suits photographs that need to open anywhere.
QOI strengths: Extremely fast lossless encode and decode; Simple, open spec. Drawbacks to weigh: Not supported by browsers or mainstream apps.
Limitations
- JPEG artefacts already in the file, such as blocking near edges and smeared colour, are kept as pixels: a lossless target preserves them faithfully rather than removing them.
- 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.
More conversions
Related tools
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Convert JPG to PNG in your browser, ready for screenshots, logos, graphics and anything that needs transparency. Batch, private, no uploads.
Convert JPG to WebP in your browser, ready for images on websites and in apps. Batch, private, no uploads.
Convert JPG to AVIF in your browser, ready for maximum compression on modern websites. Batch, private, no uploads.
Convert JPG to HEIC in your browser, a HEIF file with JPEG compression inside. Batch, private, no uploads.
Convert JPG to GIF in your browser, ready for short animations and reactions that must play everywhere. Batch, private, no uploads.
Convert JPG to PDF in your browser, one PDF page per image. Batch, private, no uploads.
Convert JPG to SVG in your browser, traced into real vector paths. Batch, private, no uploads.
Frequently asked questions
Does converting JPG to QOI lose quality?
QOI is written losslessly, so the pixels are stored exactly as decoded. Artefacts already in the JPG stay, but nothing new is lost.
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.