QUBU / IMAGE TOOLS
Your images. The format you need.
Convert static JPG, PNG, WebP and AVIF images without uploading your files.
Private by design · Processed on this deviceDrop images here
Up to 20 files · 20 MB each · 16 megapixels
Static images only. Animated files are not flattened silently.
Dimensions are preserved after orientation correction. Metadata is not retained. Colours may change when the browser converts colour profiles.
Convert images without sending your files to a server
QUBU Image Converter changes the actual image encoding, not just the filename. Choose a supported output format, review each result and download individual images or a ZIP. Files stay in this browser session; the tool does not upload their contents or save them in an account.
How to use the converter
- Select or drop up to 20 static images.
- Choose PNG, JPEG, WebP or a browser-supported output format.
- For JPEG, choose the background that replaces transparent pixels. For lossy formats, adjust quality.
- Convert, inspect the original/result previews and compare byte sizes before downloading.
Which format should you choose?
| Format | Useful for | Important limitation |
|---|---|---|
| PNG | Transparent sprites, diagrams and lossless pixel output | Can be larger than WebP or JPEG; the quality slider has no effect |
| JPEG | Photographs and opaque backgrounds | Lossy; transparency is replaced with your background colour |
| WebP | Web images with a size/quality trade-off | This tool uses browser encoding; quality affects pixels |
| AVIF | Static AVIF inputs where browser decoding is available | Output is enabled only if this browser actually encodes AVIF |
Example: preparing a transparent game sprite
Convert a static WebP sprite to PNG when your asset pipeline requires PNG. Transparency remains available and oriented pixel dimensions are preserved. Converting an already lossy WebP does not recover detail that was previously discarded. A larger PNG is not evidence of better original image quality.
What happens under the hood?
The tool checks file signatures and dimensions before decoding, draws one image at a time into a browser canvas, then checks the output MIME type, binary format signature and dimensions. Browsers may fall back to PNG for an unsupported output type; the tool rejects that fallback instead of naming a PNG file “.avif”. See the Canvas encoding documentation.
Limits and common mistakes
Each input is limited to 20 MB, 16 million pixels and 8192 pixels per side. A batch accepts 20 files and retains at most 100 MB of converted output. ZIP exports use standard uncompressed ZIP storage because encoded images are already compressed. Large files can still take time on older phones. Clear the queue to release previews and converted blobs.
This is a static-image converter. Animated WebP, APNG and AVIF sequences are rejected rather than silently losing animation. Tiled AVIF images are also rejected because their aggregate dimensions are not yet supported. GIF, SVG, HEIC, RAW and PDF are not accepted. Metadata such as EXIF and DPI settings is not retained; colour profiles may be converted by the browser. Do not use it as an archival or colour-critical conversion service.
Frequently asked questions
Are my files uploaded?
No. Image processing and ZIP creation happen on your device. Downloaded files remain wherever your browser saves them.
Does WebP to PNG preserve transparency?
For supported static images, yes. PNG keeps the decoded alpha channel. JPEG cannot keep it.
Why is the converted file larger?
Formats encode pixels differently. A lossless PNG of a photograph may be much larger than its original lossy WebP. The converter reports the actual change and does not promise smaller output.
Why is AVIF output unavailable?
AVIF decoding and AVIF encoding are separate capabilities. A browser may display AVIF but be unable to export it through Canvas. Unsupported outputs are disabled.
Can I choose an exact file size?
Not in this converter. Quality is an encoder setting, not a guaranteed KB target. Resizing and target-size compression belong to a separate tool.
Related production tools
Use the GDD builder to specify asset formats and dimensions before production, or explore the existing QUBU tools.