Free Online Batch Image Compressor

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Updated: 2026-07-11

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Drag images here, or click to select files

Supports JPG / PNG / WebP / BMP, multiple selection

Quality: 75

Output Format:

Max Width:

📖 How to Use

The Batch Image Compressor helps you compress multiple images at once, significantly reducing file sizes while maintaining acceptable visual quality. All computation happens on your device — Quality, Output Format and other inputs stay in your browser — no uploads, complete privacy.

Step-by-Step Guide

Step 1: Add Images — Drag and drop images onto the upload area, or click the button to select files. Multiple selection is supported.
Step 2: Configure Settings — Adjust compression quality (10-100; higher values produce better quality but larger files), choose output format, and set maximum width if needed.
Step 3: Compress — Click "Compress All" to start processing. Each image's progress and result will be displayed in real time.
Step 4: Download — Download individual images or click "Download All" to save all results as a ZIP file.

Quality Recommendations

Quality 85-100: Best for professional photography and print. Larger files with excellent image quality.
Quality 70-85: Recommended for everyday use. The best balance between quality and file size.
Quality 50-70: Ideal for web display and social media. Significantly smaller files.
Quality 10-50: Suitable for thumbnails and previews where visual quality is less critical.

🎯 Use Cases

Website Optimization — Batch compress product images to speed up page loading, improve SEO rankings, and enhance user experience.
E-Commerce Operations — Compress product detail images to meet platform size limits while keeping clear visual presentation.
Social Media — Process photos in bulk to meet each platform's image requirements for quick content publishing.
Email Attachments — Compress large photos to avoid email attachment size limits and ensure smooth delivery.
Blogging — Compress article images to reduce storage usage and accelerate page rendering.

💡 Technical Details

How Image Compression Works

Image compression comes in two types: lossy and lossless. Lossy compression (like JPEG) reduces file size by discarding high-frequency details that are less noticeable to the human eye, making it ideal for photographs. Lossless compression (like PNG) reduces file size by optimizing data encoding without losing any information, making it suitable for icons and screenshots. WebP combines the advantages of both approaches, typically producing smaller files than JPEG or PNG at comparable quality levels.

Canvas API Compression

This tool uses the browser's native Canvas API for image compression. Images are drawn onto a Canvas element, then re-encoded via the toBlob() method with a specified quality parameter. This process runs entirely in the browser without any server dependency. Modern browsers (Chrome, Firefox, Edge) deliver excellent JPEG and WebP compression quality.

Format Selection Tips

For photographs, we recommend converting to WebP for the best compression ratio with excellent quality. Use PNG when you need transparency. Choose JPG for maximum compatibility across all platforms and devices. Converting non-transparent PNG photos to JPG or WebP can often reduce file size by 70% or more.

❓ FAQ

Will compression noticeably reduce image quality?

It depends on the quality setting. At quality 80 or above, visual differences are barely noticeable while file size can drop 40-70%. We recommend starting with the default value of 75 and adjusting based on results.

What image formats are supported?

The tool accepts JPG/JPEG, PNG, WebP, and BMP formats. Output formats include JPG, PNG, or WebP, with WebP generally offering the best compression ratio.

Are my images uploaded to a server?

No. All compression is performed locally in your browser using the Canvas API. Your image data never leaves your device, ensuring complete privacy.

How many images can I compress at once?

There is no hard limit, but due to browser memory constraints, we recommend no more than 50 large images at a time. For smaller images (under 500KB), you can process 100+ at once.

Will PNG images stay as PNG after compression?

It depends on the output format setting. If you choose 'Keep Original Format,' PNGs remain PNGs. If you select WebP, they will be converted to WebP. Since PNG is lossless, converting to WebP typically yields much better compression.

Can I download all compressed images at once?

Yes. Click the 'Download All' button to download all compressed images as a ZIP file. You can also download individual images separately.

What does the max width setting do?

When a max width is set, images wider than the specified value will be proportionally scaled down. This not only further reduces file size but also standardizes image dimensions for consistent website display.

What should I do if compression fails?

In rare cases, compression may fail due to browser compatibility or unusual image formats. Try changing the output format or using a modern browser like Chrome or Edge. BMP files should be converted to JPG or WebP first.

🖼️ Batch Image Compressor