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Image Compressor — Compress Images Online Free

Reduce image file sizes securely in your browser using local canvas compression algorithms—no uploads required.

Image
Everything runs locally in your browser. No file upload.
Output
Compress an image to see output.
Privacy note: All processing happens entirely in your browser. No data is sent to our servers.

About this tool

The Image Compressor reduces image file sizes using lossy and lossless compression. It makes images faster to load on websites, smaller to send by email, and easier to upload within file size limits — all without significant visible quality loss.

All compression happens in your browser. Your images are never sent to any server, making this safe for confidential or personal photos.

Common use cases

  • Compressing images before uploading to WordPress, Shopify, or Squarespace
  • Reducing photo size before sending by email or WhatsApp
  • Optimising images for faster website load times
  • Meeting file size limits for online forms and job applications

How to use

  1. Upload your image by clicking or dragging and dropping.
  2. Adjust the quality slider — higher quality means less compression and larger file size; lower quality means more compression and smaller file.
  3. See the original vs compressed file size comparison.
  4. Download the compressed image.

This page is available at /tools/image-compressor/.

Understanding the result

  • Compression ratio: how much smaller the compressed file is. A 90% compression ratio means the file is 10% of its original size.
  • Lossy vs lossless: JPG compression is lossy — some image data is permanently removed. PNG can be compressed losslessly — the file is smaller but the image is pixel-perfect. WebP supports both modes.
  • Quality setting 80–85% for JPG is the sweet spot: files are 3–5× smaller than at 100% quality with no visible difference to the human eye.
  • Very high compression (quality below 60%) causes visible artifacts — blocky areas, colour banding, and blurry edges especially around text.

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FAQ

How much can I compress an image without losing visible quality?

For JPG, setting quality to 75–85% typically reduces file size by 60–75% with no visible difference on screens. Below 60% quality, compression artifacts become visible. For PNG, lossless compression reduces size by 10–30% with zero quality loss.

Does compressing an image reduce its dimensions?

No. Compression only reduces file size, not pixel dimensions. A 1920×1080 image compressed to 50KB is still 1920×1080 pixels — it just stores those pixels more efficiently.

What is the best format for web images?

WebP is the best modern format — it produces files 25–35% smaller than equivalent JPG or PNG with the same visual quality. All modern browsers support WebP. Use JPG for photographs and WebP for everything on the web where possible.

Can I compress multiple images at once?

Batch compression depends on the tool's current feature set. For large batches, you may need to process images one at a time.

Is it safe to compress confidential photos here?

Yes. All compression runs in your browser using JavaScript. Your images are never uploaded to any server — they never leave your device.