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Free Online Image Compressor

Reduce image file size without visible quality loss. Optimize photos for faster websites, smaller email attachments, and efficient storage — all processing happens privately in your browser.

Drop an image here or click to browse

Supports JPEG, PNG, and WebP

How Image Compression Works

Image compression reduces file size by removing redundant or less-important data. There are two types: lossless (no quality loss, smaller reduction) and lossy (slight quality loss, much smaller files).

Lossy compression (used for JPEG and WebP) works by exploiting how human vision works. We're less sensitive to small color variations than to brightness changes, so the algorithm can discard subtle color information without noticeable degradation. At quality level 80%, most images look identical to the original while being 60-70% smaller.

Lossless compression (used for PNG) finds patterns and repetition in pixel data and encodes them more efficiently — like zipping a file. No information is lost, but the reduction is typically 10-30%. This tool lets you choose your quality level, giving you control over the size-vs-quality tradeoff.

When You Need Image Compression

Speeding up website load times

Images account for 50%+ of most web page weight. Compressing a 2MB hero image to 200KB can cut page load time by seconds, improving both user experience and search engine rankings.

Fitting email attachment limits

Gmail caps attachments at 25MB, Outlook at 20MB. A batch of vacation photos can easily exceed this. Compressing them to 70-80% quality makes them small enough to send while still looking great on screen.

Saving storage space

Phone photos at 12MP are typically 4-8MB each. Compressing your photo library at 85% quality can free up gigabytes of storage with no perceptible quality difference when viewing on screens.

Tips for Optimal Compression

1.

Start at 80% quality and adjust from there

For most photos, 80% quality produces files 60-70% smaller with no visible difference. Only go lower if you need extreme size reduction and can tolerate some softness.

2.

Use the right format for the content

JPEG is best for photographs. PNG is best for screenshots, logos, and images with text or sharp edges. WebP offers better compression than both but has slightly less universal support.

3.

Resize before compressing

Compressing a 4000×3000 image that will display at 800×600 is wasteful. Resize to the actual display dimensions first, then compress. You'll get a much smaller file with better quality.

Features

  • Adjustable quality slider for precise control
  • Real-time preview of compressed result
  • Shows file size reduction percentage
  • Supports JPEG, PNG, and WebP formats
  • All processing in your browser — images never uploaded
  • Free, no signup or watermarks

Frequently Asked Questions

How much can I reduce file size?

Typical results: JPEG photos compress 60-80% at quality 75-80% with no visible difference. PNG screenshots compress 20-40% losslessly. Results vary based on image content — photos with lots of detail compress less than simple graphics.

Will compression make my images look bad?

At quality levels above 70%, most people cannot distinguish the compressed image from the original on a screen. Below 50%, you may notice artifacts (blockiness in JPEG, banding in gradients). The preview lets you check before downloading.

What's the difference between lossy and lossless compression?

Lossy compression (JPEG, WebP) discards some data permanently for much smaller files. Lossless compression (PNG) reorganizes data without losing anything, but achieves less reduction. Use lossy for photos, lossless for screenshots and graphics with text.

Are my images sent to a server?

No. Compression runs entirely in your browser using JavaScript. Your images stay on your device — nothing is uploaded, stored, or accessible to anyone else. This also means it works offline.

Can I compress multiple images at once?

The tool processes images individually so you can fine-tune quality settings for each one. This gives you the best balance between file size and visual quality for each specific image.

Tips & Related Workflows