PNG to QOI Converter
Convert PNG to QOI in your browser. PNG files usually come from screenshots, design exports, logos and web graphics; 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
PNG expected · other image formats also work
How to use PNG to QOI
- 1
Add your PNG 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 png to qoi
Where the QOI goes next
QOI opens in game engines, GIMP 3, ImageMagick, XnView MP and many small libraries.
QOI next to PNG
Both sides are lossless, so the size depends on how well the QOI encoder handles this picture compared with the PNG's lossless DEFLATE with a prediction filter chosen per row.
Written without a lossy pass
The QOI is written losslessly, so the pixels decoded from the PNG arrive unchanged, apart from precision beyond 8 bits per channel.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
PNG vs QOI
What changes from PNG to QOI
Encoding: the PNG uses lossless DEFLATE with a prediction filter chosen per row; 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, 8 or 16 bits per channel in the PNG; QOI allows 8 bits per channel, and the QOI written here has 8 bits per channel. 16-bit PNGs from photo and scientific software are reduced to 8 bits per channel.
Colour: RGB, greyscale, or an indexed palette of up to 256 colours in the PNG; QOI supports RGB or RGBA, tagged sRGB or linear, written here as 8-bit sRGB.
Transparency: the PNG stores it as a full alpha channel, so edges and shadows can fade smoothly; the QOI keeps it as a full 8-bit alpha channel.
Metadata: the PNG can carry text chunks, an ICC profile, physical resolution and EXIF in an eXIf chunk; QOI can carry none: a 14-byte header holds only size, channels and colour space, but nothing is copied across.
About PNG
PNG stores pixels losslessly with full alpha transparency. It is ideal for screenshots, logos, UI and anything with sharp edges, but photos saved as PNG are several times larger than JPEG.
A PNG opens with an 8-byte signature and is a chain of chunks, each with its own CRC: IHDR (size, depth, colour type), optional PLTE and tRNS for palettes, one or more IDAT chunks with the compressed rows, and IEND.
PNG files usually come from screenshots, design exports, logos and web graphics.
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 PNG to QOI makes sense
QOI is the better choice for fast lossless storage in games and tools, while PNG suits screenshots, logos, graphics and anything that needs transparency.
QOI strengths: Extremely fast lossless encode and decode; Simple, open spec. Drawbacks to weigh: Not supported by browsers or mainstream apps.
Limitations
- 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
Convert QOI to PNG in your browser, ready for screenshots, logos, graphics and anything that needs transparency. Batch, private, no uploads.
Convert PNG to JPG in your browser, with transparency filled in a colour you pick. Batch, private, no uploads.
Convert PNG to WebP in your browser, ready for images on websites and in apps. Batch, private, no uploads.
Convert PNG to AVIF in your browser, ready for maximum compression on modern websites. Batch, private, no uploads.
Convert PNG to PDF in your browser, one PDF page per image. Batch, private, no uploads.
Convert PNG to ICO in your browser, multi-size icons for favicons and Windows. Batch, private, no uploads.
Convert PNG to SVG in your browser, traced into real vector paths. Batch, private, no uploads.
Convert PNG to EPS in your browser, with transparency filled in a colour you pick. Batch, private, no uploads.
Frequently asked questions
Does converting PNG to QOI lose quality?
QOI is written losslessly, so the pixels are stored exactly as decoded. 16-bit PNGs from photo and scientific software are reduced to 8 bits per channel.
Is transparency kept in the QOI?
Yes. PNG stores it as a full alpha channel, so edges and shadows can fade smoothly, and the QOI is written with an alpha channel, so transparent areas stay transparent.
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.