Init Image Processor – A Self-Hosted Image Optimization Engine Built Like a Mini CDN

Main Features

Init Image Processor provides a complete set of professional-grade features for websites that require maximum performance:

• 100% self-hosted: No third-party services. All processing happens on your own server.
• Smart resizing: Automatically preserves aspect ratio when only width or height is provided.
• Allowed Sizes: Restricts resizing to predefined dimensions to prevent cache pollution or parameter-spam attacks.
• Flexible fit modes: cover, contain, and fill for precise layout control.
• Accurate cropping: Perfectly crop images when combined with fit + crop options.
• WebP & AVIF conversion: Reduce file size dramatically (if GD supports these formats).
• Automatic watermarking: PNG watermark with intelligent scaling and corner placement.
• Powerful caching system:
  • File-based caching
  • HTTP caching: ETag, Cache-Control, Expires
  • Atomic Write: prevents cache corruption during high-traffic parallel requests
  • Garbage Collection: automatic cleanup of old cache files via lottery or cronjob
• Advanced security:
  • Domain-restricted remote fetching (prevents SSRF)
  • MIME validation (prevents disguised script uploads)
  • Pixel-limit safeguard to avoid RAM exhaustion
  • Sanitized paths to block directory traversal
• No external dependencies: Works with PHP + GD alone—compatible with almost any shared hosting environment.

Version Information

• Version: 1.0.2
• Last Updated: 2026-02-03

System Requirements

For best performance, your server should meet the following requirements:

• PHP: 7.4 or higher (PHP 8+ recommended)
• Extensions: gd, fileinfo (cURL recommended for better reliability)
• Cache directory: writable /cache folder (permissions 755 or 775)
• HTTPS fetching: enable INIT_IMG_SSL_VERIFY

Installation & Configuration

Download init-image-processor.php and place it anywhere on your server. Then adjust the configuration section inside the file:

define('INIT_IMG_SOURCE_DOMAIN', 'https://example.com');
define('INIT_IMG_CACHE_DIR', __DIR__ . '/cache');
define('INIT_IMG_ALLOW_REMOTE', true);
define('INIT_IMG_SSL_VERIFY', true);

// Advanced options:
define('INIT_IMG_ALLOWED_WIDTHS', [320, 480, 800, 1024, 1920]);
define('INIT_IMG_MAX_PIXELS', 30 * 1024 * 1024);
define('INIT_IMG_CACHE_GC_PROBABILITY', 1000); // run GC on 1 out of every 1000 requests
define('INIT_IMG_MEMORY_LIMIT', '256M');

• INIT_IMG_SOURCE_DOMAIN: Restricts allowed image sources for SSRF protection.
• INIT_IMG_CACHE_DIR: Directory for storing processed cached images.
• INIT_IMG_ALLOWED_WIDTHS: Prevents uncontrolled cache growth.
• INIT_IMG_MAX_PIXELS: Blocks extremely large images from consuming excessive memory.
• INIT_IMG_CACHE_GC_PROBABILITY: Enables automatic periodic cache cleanup.
• INIT_IMG_MEMORY_LIMIT: Optional per-script memory limit.

URL Usage Examples

Common use cases:

• Resize image: ?src=uploads/city.jpg&w=800
• Convert to WebP: ?src=uploads/city.jpg&webp=1&q=85
• Convert to AVIF: ?src=uploads/city.jpg&avif=1
• Crop (cover mode): ?src=uploads/city.jpg&w=1200&h=600&crop=1&fit=cover
• Contain mode: ?src=uploads/city.jpg&w=600&h=600&fit=contain
• Watermark: ?src=uploads/city.jpg&w=1000&watermark=1

How It Works

The processing workflow follows these steps:

• Receive an image path or URL via the src parameter.
• Validate and authenticate the source domain.
• Fetch the original image via cURL (fallback: file_get_contents).
• Check MIME type and pixel count before loading into GD.
• Process the image according to URL parameters: resize, crop, fit, watermark, convert.
• Save the optimized output into the cache using an atomic write method.
• Return the final image along with proper HTTP cache headers (ETag, Cache-Control, etc.).

Optimizing with Nginx or Apache

You can expose clean CDN-style URLs using rewrite rules:

location /cdn/img/ {
    rewrite ^/cdn/img/(.*)$ /init-image-processor.php?$1 last;
}

Apache example:

<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteRule ^cdn/img/(.*)$ init-image-processor.php?$1 [L,QSA]
</IfModule>

Conclusion

Init Image Processor delivers a powerful, fully self-hosted image optimization workflow designed for modern high-performance websites. With built-in resizing, cropping, format conversion, watermarking, smart caching, and strict security validation, it gives you complete control over how images are processed and served—without relying on any external CDN or cloud service.

Its lightweight architecture makes it easy to integrate into any PHP project, custom framework, or internal CDN setup. By keeping all operations local, it ensures maximum speed, consistent performance, and long-term independence from third-party platforms.

If you’re looking for a fast, secure, and scalable image processing solution that runs entirely on your own server, Init Image Processor is a reliable and future-proof choice within the Init HTML ecosystem.

Install it, apply your rewrite rules, and enjoy CDN-style image optimization directly on your server.