A high-performance batch image compression service built with Node.js and Sharp. Compress images to multiple formats (WebP, AVIF, PNG, JPEG, GIF) with smart quality optimization and resize capabilities.

• 🚀 High-Performance: Multi-format support with optimized compression algorithms
• 📦 Batch Processing: Handle up to 20 files per request (up to 50MB each)
• 🎨 Multiple Formats: WebP, AVIF, JPEG, PNG, GIF with auto-detection
• 🔧 Smart Optimization: Automatic quality adjustment based on image properties
• 📏 Resize Support: Optional width-based resizing with Lanczos3 kernel
• 🌐 Web UI: Interactive drag-and-drop interface included
• 🐳 Docker Ready: Production-ready Docker multi-stage build
• ⚙️ Highly Configurable: Comprehensive environment variables

• Node.js 18+ or Docker

# Clone repository
git clone <repository-url>
cd img-optimize

# Install dependencies
cd server
npm install

# Run server
npm start

The server will start on http://localhost:3000

# Build image
docker build -t imgpress .

# Run container
docker run -d \
  -p 3000:3000 \
  -e PORT=3000 \
  imgpress

Endpoint: POST /compress/one

Request:

• Content-Type: multipart/form-data
• Form field: file (required) - Image file to compress

Query Parameters:

Response (Success):

{
  "name": "photo.jpg",
  "mime": "image/webp",
  "originalSize": 2048576,
  "compressedSize": 614400,
  "savedBytes": 1434176,
  "ratio": 70.0,
  "data": "UklGRi4AAABXRUJQVlA4IBoAAAA...",
  "error": false
}

Response (Error):

{
  "name": "photo.jpg",
  "originalSize": 2048576,
  "error": true,
  "message": "Image too large: 25000×25000px (max 20000px per side)"
}

cURL Example:

# Basic compression
curl -X POST \
  -F "file=@image.jpg" \
  http://localhost:3000/compress/one

# Custom format and quality
curl -X POST \
  -F "file=@image.jpg" \
  "http://localhost:3000/compress/one?format=avif&quality=75&width=1200"

# Auto-detect format
curl -X POST \
  -F "file=@image.jpg" \
  "http://localhost:3000/compress/one?format=auto"

JavaScript Example:

const formData = new FormData();
formData.append('file', fileInput.files[0]);

const response = await fetch('/compress/one?format=webp&quality=80&width=1600', {
  method: 'POST',
  body: formData
});

const result = await response.json();
if (!result.error) {
  // Download or display compressed image
  const imageBuffer = Buffer.from(result.data, 'base64');
  // ... handle image
}

Server behavior is controlled via environment variables:

# Port & Timeouts
PORT=3000
SERVER_TIMEOUT_MS=300000
KEEP_ALIVE_TIMEOUT_MS=360000
HEADERS_TIMEOUT_MS=361000
COMPRESS_TIMEOUT_MS=300000

# Image Size Limits
MAX_IMAGE_SIDE_PX=20000          # Max width/height per side
MAX_IMAGE_MEGAPIXELS=200          # Max total megapixels
MAX_FILE_SIZE_MB=50               # Max file size per upload
MAX_FILES=20                       # Max files per request

# Compression Defaults
DEFAULT_QUALITY=80                # Default quality (1-100)
DEFAULT_WIDTH=1600                # Default resize width
MAX_QUALITY_NO_ALPHA=85           # Max quality for images without alpha
MAX_QUALITY_WITH_ALPHA=90         # Max quality for images with alpha

# Advanced
DITHER_MAX=0.7                    # Dither amount for PNG (max)
DITHER_MIN=0.3                    # Dither amount for PNG (min)
SHARP_CONCURRENCY=0               # 0 = auto, >0 = limit concurrent operations

The service automatically caps quality based on image properties:

• Images without alpha channel → capped at MAX_QUALITY_NO_ALPHA (85)
• Images with transparency → capped at MAX_QUALITY_WITH_ALPHA (90)
• This ensures optimal file size without quality degradation

• Resize: Uses Lanczos3 kernel for high-quality downsampling
• Color Space: Converts to sRGB for consistent output
• Optimization:
  • JPEG: MozJPEG + progressive encoding + optimized scanning
  • PNG: Maximum compression + adaptive filtering + dithering
  • AVIF: 4:2:0 chroma subsampling for better compression
  • GIF: Frame analysis + dithering for smooth gradients

Open http://localhost:3000 in your browser to access the ImgPress web interface with:

• Drag & drop image upload
• Format selection
• Quality control
• Real-time compression stats
• Batch processing

img-optimize/
├── server/
│   ├── server.js         # Express server & compression logic
│   └── package.json      # Dependencies
├── client/
│   ├── index.html        # Web UI
│   ├── script.js         # Frontend logic
│   └── styles.css        # Styling
├── Dockerfile            # Container configuration
└── README.md             # This file

cd server
npm install
npm start

Visit http://localhost:3000

• Per File: 50 MB max
• Per Request: 20 files max
• Image Dimensions: 20,000 px per side max
• Total Megapixels: 200 MP max

Common error messages:

The API accepts requests from all origins. Customize CORS in server.js if needed:

res.setHeader('Access-Control-Allow-Origin', '*') // Change '*' to specific domain

MIT

For issues, features, or questions, please open an issue on the repository.