ProRank SEO
Docs/Performance/Image Optimisation

Image Optimisation

Automatic image compression with Jpegli, AVIF, JXL, WebP, and intelligent lazy loading

2025 Edition

Overview

ProRank SEO's Image Optimisation delivers enterprise-grade image processing with cloud and local optimisation, AI-powered smart cropping, and automatic Jpegli/WebP/AVIF/JXL generation. Process millions of images with our scalable infrastructure, reducing sizes by up to 85% while maintaining perfect visual quality.

80% Smaller

Reduce image file sizes without visible quality loss

Next-gen Formats

Automatic conversion to Jpegli/WebP/AVIF/JXL with smart fallbacks

Lazy Loading

Load images only when they enter the viewport

License Tiers & Quotas

🏆 Agency License:100,000 images/year (8,333/month)
💼 Business License:20,000 images/year (1,666/month)
⭐ Pro License:5,000 images/year (416/month)
💳 Additional Credits:30,000 images for $5

Processing Methods

Cloud Optimisation

Powered by prorank.io

  • Sharp-based pipeline with libvips 8.17 + Jpegli/AVIF/JXL
  • pngquant → oxipng → ECT final pass for PNG
  • AI-powered smart cropping
  • JPEG XL ready for 2025
  • No server resource usage

Local Optimisation

On your server

  • GD Library or ImageMagick
  • No external dependencies
  • Complete data privacy
  • Works offline
  • Limited by server resources

Automatic Fallback

ProRank automatically selects the best optimisation method based on your license and server capabilities. Cloud optimisation is preferred for Pro+ licenses, with automatic fallback to local processing if needed.

Automatic Compression

Smart Compression Engine

Every image uploaded to your WordPress media library is automatically compressed using advanced algorithms that maintain visual quality while dramatically reducing file size.

Lossless Compression

  • Perfect for logos and graphics
  • No quality loss whatsoever
  • 20-30% size reduction
  • Preserves transparency

Lossy Compression

  • Ideal for photographs
  • Imperceptible quality difference
  • 60-80% size reduction
  • Adjustable quality levels

Compression Results

JPEG Photos

Original:2.4 MB
Optimised:420 KB
82% smaller

PNG Graphics

Original:856 KB
Optimised:198 KB
77% smaller

WebP Conversion

JPEG:420 KB
WebP:168 KB
60% smaller

Modern Format Conversion

WebP & AVIF Support

Automatically generates WebP and AVIF versions of your images, serving the most efficient format based on browser support while maintaining fallbacks for older browsers.

WebP Format

  • • 25-35% smaller than JPEG
  • • Supports transparency
  • • 95% browser support
  • • Lossless & lossy options

AVIF Format

  • • Up to 91% compression vs original (verified benchmarks)
  • • Better quality at low bitrates
  • • 95%+ browser support (Chrome, Firefox, Safari, Edge)
  • • HDR support

Automatic Format Selection

Generated HTMLhtml
<!-- ProRank automatically generates picture elements with fallbacks -->
<picture>
  <source srcset="image.avif" type="image/avif">
  <source srcset="image.webp" type="image/webp">
  <img src="image.jpg" alt="Description" loading="lazy" width="800" height="600">
</picture>

Smart Delivery

ProRank automatically detects browser capabilities and serves the most efficient format. Modern browsers get WebP/AVIF, while older browsers receive optimised JPEG/PNG.

Responsive Images

Responsive Image Support

ProRank works with WordPress's built-in responsive image system. When a CDN is configured, ProRank rewrites srcset URLs to serve optimised images from your CDN.

How It Works

  • ProRank works with WordPress's built-in responsive image srcset system
  • When a CDN is configured, ProRank rewrites srcset URLs for CDN delivery
  • Optional @2x retina image generation for high-DPI displays
Responsive Image Outputhtml
<!-- WordPress generates srcset with registered image sizes -->
<!-- ProRank rewrites URLs for CDN delivery when configured -->
<img 
  src="image.jpg"
  srcset="image-300x200.webp 300w,
          image-768x512.webp 768w,
          image-1024x683.webp 1024w"
  sizes="(max-width: 768px) 100vw, 1024px"
  alt="Responsive image"
  loading="lazy"
  width="1024"
  height="683">

Intelligent Lazy Loading

Progressive Image Loading

Images load only as they approach the viewport, reducing initial page weight and improving Core Web Vitals scores.

Native Lazy Loading

  • Browser-native implementation
  • No JavaScript required
  • SEO friendly
  • Automatic for all images

Smart Loading Features

  • Skip lazy load for above-fold
  • Progressive enhancement

LCP Optimisation

ProRank skips lazy loading on early images (first ~10 images on the page) to avoid delaying the Largest Contentful Paint element.

Cloud Processing Features

Cloud Image Processing

When using cloud optimisation, images are sent to the prorank.io processing API which handles format conversion, compression, and optional smart cropping.

Smart Cropping (Cloud)

  • Crop focus and face detection flags sent to cloud API
  • Processing handled server-side by prorank.io

Bulk Optimisation

Optimise Existing Images

Retroactively optimise all existing images in your media library with one click. Process thousands of images in the background without affecting site performance.

Bulk Processing Features

  • Background processing
  • Resume from interruptions
  • Progress tracking
  • Detailed statistics
  • Keep original backups
  • Restore originals anytime
  • Skip already optimised
  • Filter by date/size

Reliability & Recovery

Enterprise-Grade Reliability

Built with production resilience in mind, featuring automatic retry mechanisms, queue management, and comprehensive error recovery to ensure no image is left behind.

Retry Mechanism

  • Exponential backoff (1s, 2s, 4s)
  • 3 automatic retry attempts
  • Failed queue for manual retry
  • Network error resilience

Backup & Recovery

  • Original image preservation
  • One-click restoration
  • Single backup copy per image

Production Safety

All optimisation operations are non-destructive. Original images are preserved in a backup directory, allowing instant restoration if needed. Failed optimisations are queued for automatic retry during the next processing cycle.

CDN Integration

Global Image Delivery

Automatically serve optimised images through your CDN with on-the-fly transformation support for dynamic resizing and format conversion.

Cloudflare

  • • Cache purge via Zone API
  • • CDN URL rewriting

BunnyCDN

  • • Cache purge API
  • • CDN URL rewriting

Custom CDN

  • • URL rewriting
  • • Origin pull
  • • Cache control

Usage Monitoring & Statistics

Statistics Dashboard

The Image Optimisation settings page displays live statistics from your media library.

Displayed Metrics

  • Media Library Images — total images in your library
  • Modern-ready Images — images with WebP/AVIF versions generated
  • Space Saved — total bytes saved by optimisation
  • Optimisation Rate — percentage of eligible images optimised
  • Backup Storage Used — disk space used by original backups (when backups are enabled)

When cloud optimisation is active, quota usage and remaining credits are also displayed.

Available Statistics

  • • Total images optimised
  • • Total size saved
  • • Average compression ratio
  • • Cloud quota usage

Configuration

WordPress Settingsjavascript
// Access settings in WordPress Admin
// Settings > ProRank SEO > Performance > Image Optimisation

const imageSettings = {
  // Processing Method
  optimization_method: 'cloud', // 'cloud' | 'local' | 'auto'
  
  // Quality Settings
  jpeg_quality: 85,        // 1-100
  webp_quality: 80,        // 1-100
  avif_quality: 75,        // 1-100
  
  // Format Generation
  webp_enabled: true,      // Generate WebP versions
  avif_enabled: true,      // Generate AVIF versions
  
  // Processing Options
  optimize_on_upload: true,     // Auto-optimise new uploads
  background_mode: true,        // Use background processing
  preserve_metadata: false,     // Strip EXIF data
  
  // Advanced Options
  max_width: 2560,             // Maximum image width
  max_height: 2560,            // Maximum image height
  backup_originals: true,      // Keep original files
  auto_retry_failed: true,     // Retry failed optimisations
  
  // CDN Integration
  cdn_enabled: false,          // Enable CDN delivery
  cdn_provider: 'cloudflare',  // CDN provider
  cdn_url: '',                 // Custom CDN URL
};
Programmatic Controlphp
// Image optimisation is managed through the WordPress admin UI
// and REST API endpoints. Settings are configured at:
// ProRank SEO > Performance > Image Optimisation

// REST API endpoints:
// GET  /wp-json/prorank-seo/v1/image-optimization/settings
// POST /wp-json/prorank-seo/v1/image-optimization/settings
// POST /wp-json/prorank-seo/v1/image-optimization/optimize
// POST /wp-json/prorank-seo/v1/image-optimization/bulk-optimize
// POST /wp-json/prorank-seo/v1/image-optimization/restore

Performance Impact

Typical Results with Image Optimisation

75%

Smaller Images

2.3s

Faster LCP

60%

Less Bandwidth

95+

PageSpeed Score

Core Web Vitals Impact

Sites using ProRank's Image Optimisation typically see LCP improve by 40-60%, with many achieving green Core Web Vitals scores across all metrics.

Troubleshooting

Images not optimising?

  • • Check PHP memory limit (256MB recommended)
  • • Verify GD or ImageMagick is installed
  • • Check file permissions on uploads folder
  • • Review error logs for specific issues

WebP not serving?

Ensure your server supports WebP mime type and .htaccess rules are properly configured. Check browser dev tools network tab to verify WebP delivery.

Next Steps