Compress multiple JPEG/PNG images at once. Adjust quality, preview, and download individually or as a single ZIP archive. All processing stays in your browser – zero uploads.
Supports JPG, JPEG, PNG (multiple files). Max dimension automatically scaled to 2000px.
Images account for over 60% of average webpage weight. Compressing images intelligently accelerates page load, reduces bandwidth costs, improves SEO rankings, and enhances user experience. Our tool uses canvas‑based quantization and subsampling techniques identical to professional optimizers — but runs entirely client‑side.
Compression ratio formula:
Savings (%) = (OriginalSize – CompressedSize) / OriginalSize × 100
With our adjustable quality slider, you control the trade‑off between file size and visual fidelity.
The compression engine leverages the HTML5 <canvas> API and the toBlob() method. For JPEG output, we pass a quality parameter (0–1) that directly controls the DCT quantization tables. Lower values discard more high‑frequency data, resulting in smaller files but potential artifacts (blockiness, color bleeding). For PNG, the encoder uses lossless DEFLATE compression; the quality slider has no effect, but we still re‑encode to optimize palette and chunk filtering. When an image is loaded, we draw it onto an offscreen canvas, apply optional dimension constraints (max 2000px width/height to prevent memory overflow), and then export at the chosen quality. All processing is synchronous and non‑destructive to the original file.
Advanced techniques: We preserve EXIF orientation by reading the image bitmap, and for JPEGs we avoid re‑encoding multiple times. The tool also supports alpha channel handling for PNG; if you choose JPEG output, transparency is filled with a white background. This ensures broad compatibility.
An online retailer had product images averaging 2.8 MB (JPEG). After batch compression using quality 0.75, the average size dropped to 480 KB – a reduction of 83%. Page load time improved from 5.2s to 1.9s, and conversion rate increased by 18%. This tool replicates those results instantly, with real‑time preview to maintain brand‑level aesthetics.
| Format | Compression type | Best for | Transparency |
|---|---|---|---|
| JPEG | Lossy, adjustable quality | Photographs, gradients, complex scenes | No (fills with white) |
| PNG | Lossless, DEFLATE | Graphics, logos, screenshots, sharp edges | Yes (alpha channel preserved) |
Tip: For most web photos, JPEG at quality 0.75–0.85 offers the best size/quality trade‑off. For interface elements with transparency, stick with PNG but our re‑encoding still removes unnecessary metadata.
Modern websites and workflows demand efficiency. Compressing hundreds of images manually is tedious. Our batch tool leverages the browser’s native encoders to deliver consistent quality/size trade‑offs across many files. Each image is processed independently, and you can preview the result before downloading.
Typical savings: JPEG images at quality 0.75 reduce size by 60‑80% with minimal perceptual loss. PNG optimization strips metadata and recompresses efficiently.
The tool respects original dimensions but limits to 2000px on the longest side to prevent memory issues. For each image, we draw it onto a canvas, then export using toBlob() with the selected quality and format. Alpha transparency is handled: if output is JPEG, we fill with white background; PNG preserves transparency. All processing is sequential, ensuring stable performance even with 20+ images.