How does browser-based image compression work?

The tool uses the HTML5 Canvas API to re-encode images. It draws the image on an invisible canvas, then exports it with the specified quality setting and output format. For JPEG and WebP, reducing quality removes visual data the human eye barely notices, achieving significant file size reduction.

Is my image data safe?

Yes, 100%. All compression happens in your browser using JavaScript and the Canvas API. Your images are never uploaded to any server. You can verify this by checking your browser's Network tab while compressing — zero network requests are made.

What image formats are supported?

This tool accepts PNG, JPEG, WebP, GIF, and BMP images as input. Output formats include JPEG (best compression ratio), WebP (modern format with excellent quality-to-size ratio), and PNG (lossless, best for graphics with transparency).

🖼️ Image Compressor

Compress PNG, JPEG, and WebP images up to 80% smaller. 100% in-browser — your images never leave your device.

📷

Drop images here or click to browse

Supports PNG, JPEG, WebP, GIF, BMP • Max 20 MB per image

Quality: 75% Output: Max width:

Why Compress Images?

Images account for 50-80% of a typical web page's total size. Unoptimized images slow down page load times, increase bandwidth costs, and hurt SEO rankings. Google's Core Web Vitals specifically measure Largest Contentful Paint (LCP), which is directly impacted by image sizes.

Key Features

Adjustable quality — Fine-tune the quality slider from 1-100%. For most photos, 70-80% quality is visually identical to the original but 50-70% smaller
Format conversion — Convert PNG to WebP for 25-35% smaller files, or JPEG to WebP for modern browsers
Resize on compress — Optionally limit max width to 1920px, 1280px, 800px, or 640px for web-optimized images
Batch processing — Compress multiple images at once with a single download for all
Privacy-first — Zero server uploads. Everything runs via Canvas API in your browser

Recommended Quality Settings

85-95% — High quality. Best for portfolio sites and photography. ~20-40% file size reduction
70-85% — Balanced. Ideal for blog posts, e-commerce product images. ~40-60% reduction
50-70% — Aggressive. Good for thumbnails, social media, email images. ~60-80% reduction
Below 50% — Maximum compression. Visible quality loss but good for previews and placeholders

WebP vs JPEG vs PNG

WebP — Best overall format for web. 25-35% smaller than JPEG at same quality. Supported by all modern browsers (Chrome, Firefox, Safari 14+, Edge)
JPEG — Best for photographs and complex images. Lossy compression. No transparency support. Universal compatibility
PNG — Best for graphics, logos, and images requiring transparency. Lossless but larger file sizes. Use PNG-8 for simple graphics

Why Some Images Don't Get Smaller

If a file shows "Already optimal", it means the original is already well-compressed and re-encoding it would actually increase the file size. This is common with:

Optimized PNGs — PNG is a lossless format, so the quality slider has no effect. Tools like TinyPNG or Photoshop's "Export for Web" already apply advanced PNG compression (palette reduction, DEFLATE tuning) that the browser's Canvas API cannot replicate
Small images — Very small images or icons have little redundancy to compress further
Pre-compressed files — Images already processed by other optimization tools

Tip: To reduce PNG file sizes, try converting to WebP or JPEG using the Output format dropdown — this typically saves 25-70% even on already-optimized PNGs.