How much can I reduce image file size without visible quality loss?

For JPEG, going from 100% to 80% quality typically reduces file size by 50–70% with virtually no visible difference on screen or print. For PNG with flat colors, switching to WebP lossless can reduce size by 25–35%. The right quality depends on your use case — web thumbnails can use 60–70% quality; print assets should stay at 85–95%.

What is the difference between JPEG compression and PNG compression?

JPEG uses lossy compression — pixels are mathematically approximated. Lower quality = smaller file but some detail is lost. PNG uses lossless compression — every pixel is preserved exactly, but file sizes are larger. PNG compression only removes redundancy in the data, not actual image information. For photos, JPEG or WebP is more efficient; for screenshots, icons, or images with transparency, PNG or WebP lossless is appropriate.

Will compressing an already-compressed JPEG make it worse?

Yes, re-compressing JPEG introduces "generation loss" — each compression cycle degrades quality slightly. This tool minimizes damage by using a high-quality decoder (jsquash), but the principle applies. If preserving maximum quality is critical, compress from the original RAW or lossless source, not from an already-compressed JPEG.

Why is PNG compression so much less effective than JPEG?

PNG lossless compression has physical limits — complex photos with millions of unique colors can only compress so much without losing data. For photos, WebP lossy or JPEG will always be smaller. PNG excels at artificial images: screenshots, diagrams, logos, and UI elements with few unique colors, where compression ratios of 5–10× are achievable.

Is there a lossless way to reduce JPEG file size?

Standard JPEG compression is inherently lossy. There are lossless JPEG optimization tools (like jpegtran) that strip metadata and optimize Huffman coding without touching pixels — typically saving 2–8%. This tool uses lossy re-encoding at your chosen quality. For lossless JPEG optimization, consider ImageOptim on macOS or Squoosh with its Mozjpeg encoder at 100% quality.

Compress Image — Reduce File Size, Keep Quality

Shrink image file sizes before uploading to websites, sending by email, or sharing on social media. Drag and drop your images and use the quality slider to find the right balance between file size and visual quality. The output format matches the input — JPEG stays JPEG, PNG stays PNG, and so on. Everything runs locally in your browser using high-performance WebAssembly codecs.

Quality75%

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Up to 50.0 MB per file

How to use this tool

Upload your images
Drop one or more JPEG, PNG, WebP, or AVIF images. Batch compression is supported — all files process in parallel.
Adjust the quality slider
The default setting of 75% reduces most images by 40–70% with no perceptible quality loss. Slide lower for smaller files or higher for maximum quality.
Click Compress
Each image is decoded and re-encoded at your chosen quality using the appropriate codec (JPEG for photos, PNG lossless, WebP for web graphics).
Download and compare
Each result shows the output file size and the percentage reduction. Download individually or as a ZIP archive.

Frequently asked questions

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Compress Image — Reduce File Size, Keep Quality

How to use this tool

Frequently asked questions

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