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The Dynamic Images API lets you resize, crop, and transform images in real time by appending query parameters to image URLs. No pre-processing or multiple file versions required, just add parameters to your image URLs and Bunny Optimizer handles the rest.

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How it works

Add transformation parameters to any image URL served through your Pull Zone: 
https://yourzone.b-cdn.net/image.jpg?width=500&sharpen=true
Bunny Optimizer processes the transformation on the first request and caches the result at the edge. Subsequent requests are served instantly from the global CDN cache. All transformations preserve the original image. You can request the same source image with different parameters to generate multiple variations without storing duplicates.

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Prerequisites

Before using Dynamic Images, ensure:
  1. Bunny Optimizer is enabled on your Pull Zone
  2. Dynamic Image API is enabled in Optimizer settings (Optimizer → Settings)
  3. (Optional) Create Image Classes for predefined transformation presets

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Quick examples

Perfect for responsive images across different devices and screen resolutions. Resize while maintaining aspect ratio: 
https://yourzone.b-cdn.net/image.jpg?width=500
https://yourzone.b-cdn.net/image.jpg?height=300
Create thumbnails with specific aspect ratios: Ideal for product listings and galleries. 
https://yourzone.b-cdn.net/image.jpg?aspect_ratio=16:9&width=256
https://yourzone.b-cdn.net/image.jpg?aspect_ratio=1:1&height=400
Crop to specific dimensions: 
https://yourzone.b-cdn.net/image.jpg?crop=800,600
https://yourzone.b-cdn.net/image.jpg?crop=400,300&crop_gravity=north
Smart cropping with face detection: 
https://yourzone.b-cdn.net/image.jpg?face_crop=600,600
Adjust colors and exposure: 
https://yourzone.b-cdn.net/image.jpg?brightness=10&contrast=5&saturation=15
https://yourzone.b-cdn.net/image.jpg?gamma=20&hue=33
Apply filters and effects: Great for privacy protection and brand consistency. 
https://yourzone.b-cdn.net/image.jpg?sharpen=true&blur=0
https://yourzone.b-cdn.net/image.jpg?sepia=75
Optimize quality and format: Essential for performance optimization and social media. 
https://yourzone.b-cdn.net/image.jpg?quality=75&format=webp
Combine multiple transformations: 
https://yourzone.b-cdn.net/image.jpg?width=800&crop=600,400&brightness=5&sharpen=true&quality=80
https://yourzone.b-cdn.net/image.jpg?aspect_ratio=16:9&gamma=10&saturation=10&format=webp

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Available transformations

Resizing

Resize by width or height while maintaining aspect ratio

Cropping

Crop to dimensions, aspect ratios, or focal points

Face Detection

Automatically detect and crop around faces

Color Manipulation

Adjust saturation, hue, contrast, tint, and sepia

Luminosity

Control brightness and gamma for exposure correction

Blur and Sharpen

Apply blur effects or enhance sharpness

Reflections and Rotations

Flip, flop, and rotate in 90-degree increments

Quality

Control compression levels and file size

Formats

Convert between JPEG, PNG, WebP, and GIF

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Transformation order

When combining multiple parameters, transformations are applied in a specific order:
  1. Crop operations (crop, aspect_ratio, focus_crop, face_crop)
  2. Resize operations (width, height)
  3. Reflections and rotations (flip, flop, rotate)
  4. Color and luminosity adjustments (brightness, gamma, contrast, saturation, hue, tint, sepia)
  5. Filters (blur, sharpen)
  6. Format and quality (format, quality)
Understanding this order helps you predict the final output when combining multiple transformations.

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Performance and caching

All transformations are processed once and cached at the edge:
  • First request: Bunny Optimizer processes the transformation and stores the result in the global CDN cache
  • Subsequent requests: Served instantly from the nearest edge location
  • Cache invalidation: Purging the original image also purges all transformed variations
This approach ensures fast delivery while maintaining flexibility. You can request new transformation combinations at any time without impacting performance of existing cached variations.

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Best practices

Use Image Classes for consistency: Define common transformation patterns as Image Classes to maintain consistency and simplify URLs. Combine transformations in single requests: Apply multiple transformations in one URL rather than chaining multiple requests to reduce processing overhead. Test quality settings: Always verify that quality and compression settings produce acceptable visual results on target devices. Leverage automatic format conversion: Enable WebP in Optimizer settings to automatically serve modern formats to supported browsers. Consider transformation order: Remember that crops are applied before resizing. Base crop dimensions on the original image size, not the target size. Monitor bandwidth savings: Use quality control and format conversion together to achieve significant file size reductions while maintaining visual quality.