SilentCanoe
SilentCanoe Utilities
/ Image Resizer & Compressor

Image Resizer & Compressor

Batch resize and compress images to WebP, AVIF, JPEG, or PNG. Works offline. Zero uploads.

🔒 Images are processed entirely in your browser using the Canvas API. No images are uploaded or transmitted anywhere.

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JPG, PNG, WebP, GIF, BMP, AVIF — multiple files OK

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Frequently Asked Questions

Does this tool support AVIF output?

AVIF output is supported on browsers that implement canvas.toDataURL('image/avif'). Chrome 94+ and Firefox 113+ support it. If your browser does not support AVIF encoding, the tool automatically falls back to WebP and shows a warning badge on each affected file.

How does the quality slider affect file size?

The quality slider (1–100) controls the lossy compression level for JPEG, WebP, and AVIF outputs. Lower values produce smaller files with more visible compression artefacts. A setting of 80–85 is a good balance for most photos. PNG is lossless and ignores the quality slider entirely.

Is there a maximum file size limit?

There is no hard limit enforced by this tool. The practical limit depends on your browser's available memory. Very large images (e.g. 50 MB RAW exports) may cause slowness or browser warnings. Images are processed one at a time to minimise peak memory usage.

How does the ZIP download work?

After processing, click "Download All as ZIP". The tool uses JSZip (running entirely in your browser) to package all output files into a single .zip archive, which is then triggered as a standard browser download via a temporary object URL. No server is involved at any point.

How does the tool maintain aspect ratio?

In Scale %, Max Width, and Max Height modes the original aspect ratio is always preserved automatically. In Exact mode you can choose: Cover (fills the target box and crops the overflowing edges), Contain (fits entirely inside the box, adding transparent or black padding), or Stretch (ignores aspect ratio and fills exactly).