Free Online Image Compressor & Optimizer

How does image compression work?

The browser decodes pixels, optionally resizes them, and encodes a new JPEG, PNG, or WebP file. Quality settings mainly affect lossy formats; PNG encoding behavior depends on the browser.

Lossy versus lossless compression

Lossy compression removes visual information to achieve smaller files. Lossless compression preserves decoded pixels but usually produces larger output. Always inspect the preview at the size users will actually see.

Recommended quality settings

• Use roughly 75–85% for many photographic JPEG and WebP images.
• Resize oversized images to their maximum rendered dimensions before chasing codec settings.
• Keep PNG for transparency or crisp graphics when WebP is not appropriate.
• Test text, gradients, product imagery, and screenshots separately.

Performance and privacy

Files stay in the browser. A Web Worker with OffscreenCanvas is used when supported; a responsive main-thread fallback is provided otherwise. Per-file and batch limits prevent uncontrolled memory use.

How to use Image Compressor & Optimizer

1. Add one or more JPEG, PNG, or WebP images.
2. Choose quality, output format, and optional maximum dimensions.
3. Compress locally and compare previews, dimensions, and file sizes.
4. Download individual results or all completed images as a ZIP.

Input and output example

Example input

2400 × 1600 JPEG, 2.8 MB, quality 82%, maximum width 1600 px

Example output

1600 × 1067 JPEG with a smaller file size; exact savings depend on image detail and browser encoder.

Troubleshooting

• A PNG may become larger because browser encoders and source optimization differ.
• Very large pixel dimensions can exhaust mobile memory even when file size is modest.
• If WebP encoding is unavailable, keep the original format or use a modern browser.

Limitations

Canvas re-encoding usually strips metadata and does not provide the full codec controls of specialist native software. Visual quality is subjective and must be reviewed.

Developer tips

• Resize to the largest rendered dimensions before adjusting quality.
• Use responsive images and explicit dimensions in production markup.
• Test screenshots, gradients, transparency, and photographs with different settings.

Browser compatibility

Current versions of Chrome, Edge, Firefox, and Safari are supported. File, clipboard, Web Crypto, worker, canvas, and download capabilities can vary by browser and security context; the interface reports unavailable operations rather than uploading data as a fallback.

Supported formats

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