How to Use
- Drag and drop one or more images onto the upload area, or click it to browse your device. Supported formats: JPEG, PNG, and WebP.
- Adjust the Quality slider to control how much compression is applied. Lower values produce smaller files with some quality loss.
- Optionally choose an Output format — Auto keeps the original format, or you can convert to JPEG, PNG, or WebP.
- Optionally set Max dimensions to resize large images while maintaining aspect ratio.
- Click Compress All to process every image in the list.
- Download individual images with their download button, or click Download All to save every compressed image at once.
Tips
- A quality of 70–80% is a great starting point — it usually cuts file size in half with minimal visible change.
- Converting PNG screenshots to JPEG or WebP can dramatically reduce file size.
- WebP format generally produces the smallest files for photos while keeping good quality.
- Use the max-dimensions option to batch-resize images for web use (e.g. 1200 × 800).
- You can add more images at any time, even after compressing a batch.
Frequently Asked Questions
Are my images uploaded to a server?
No. All compression happens locally in your browser using the HTML5 Canvas API. Your images are never sent to any server, keeping them completely private.
What quality setting should I use?
A quality of 70-80% is a great starting point — it typically cuts file size in half with minimal visible quality change. For web thumbnails you can go lower; for print use higher values.
Which output format produces the smallest files?
WebP generally produces the smallest file sizes for photos while maintaining good quality. Converting PNG screenshots to WebP or JPEG can dramatically reduce file size.
Can I compress multiple images at once?
Yes. You can upload multiple images at once and click Compress All to process the entire batch. Use Download All to save every compressed image in one action.
Can I resize images as well as compress them?
Yes. Use the Max Dimensions option to set a maximum width or height. The tool will scale images down while preserving the original aspect ratio.
About
Image Compressor reduces the file size of your JPEG, PNG, and WebP images entirely inside your browser. Nothing is uploaded to a server — all processing happens locally on your device, keeping your images completely private.
The tool uses the HTML5 Canvas API to re-encode images at adjustable quality levels. It supports batch compression, format conversion, and optional resizing. Works on any modern browser, desktop or mobile, with no installs or sign-ups required.
From the build: the compression path is just `canvas.toBlob` with a quality parameter, which sounds anticlimactic until you realise it means the browser's native JPEG/WebP encoder is doing the work — faster and better-tuned than anything we could ship as JavaScript. The trickier piece is the resize step: we use a single-pass `drawImage` for speed, which is fine for moderate downscales, but for very large source images we'd need to step through multiple intermediate sizes to avoid aliasing. We capped the max input at something where the single pass still looks clean. Format conversion is just changing the MIME type passed to toBlob — the canvas is format-agnostic.