DotNetBrightener.UploadService.ImageOptimizer

Image optimization and resizing functionality for DotNetBrightener Upload Service.

🔒 Migration Notice - Version 2026.0.1+

Version 2026.0.1+ has migrated from Magick.NET to SkiaSharp due to security vulnerability CVE-2025-65955.

Security Details

• Vulnerability: CVE-2025-65955 (CVSS 4.9/10 - Moderate)
• Affected Package: Magick.NET v14.9.1
• Issue: Use-after-free/double-free in ImageMagick's Magick++ layer
• Resolution: Migrated to SkiaSharp (Microsoft-backed, actively maintained)

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🚀 Breaking Changes

Old Method (Deprecated)

services.AddUploadService(config) .UseImageMagickOptimizer(); // ⚠️ Deprecated - shows warning

New Method (Recommended)

services.AddUploadService(config) .UseSkiaSharpOptimizer(); // ✅ Use this instead

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✨ Benefits of SkiaSharp

• ✅ No security vulnerabilities - Actively maintained by Microsoft
• ✅ Better cross-platform support - Windows, Linux, macOS, iOS, Android
• ✅ High performance - Native Skia graphics engine
• ✅ Modern .NET API - Designed for .NET Core and beyond
• ✅ Comprehensive graphics features - More than just image resizing

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📦 Installation

dotnet add package DotNetBrightener.UploadService.ImageOptimizer

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📖 Usage

Basic Setup

using Microsoft.Extensions.DependencyInjection; // In your Startup.cs or Program.cs services.AddUploadService(configuration) .UseSkiaSharpOptimizer();

Advanced Configuration

services.AddUploadService(configuration) .UseSkiaSharpOptimizer() .ConfigureUploadOptions(options => { options.MaxFileSize = 10 * 1024 * 1024; // 10MB options.AllowedFileExtensions = new[] { ".jpg", ".jpeg", ".png", ".gif", ".webp" }; });

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🔄 Migration Guide

Step 1: Update Package Reference

No changes needed if using centralized package management. The package will automatically use SkiaSharp.

Step 2: Update Code

Before:

services.AddUploadService(config) .UseImageMagickOptimizer();

After:

services.AddUploadService(config) .UseSkiaSharpOptimizer();

Step 3: Test Your Application

1. Build your application
2. Run unit tests
3. Test image upload and resize functionality
4. Verify image quality meets your requirements

Backward Compatibility

The old UseImageMagickOptimizer() method still works but:

• Shows an [Obsolete] warning during compilation
• Internally redirects to UseSkiaSharpOptimizer()
• Will be removed in the next major version

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📝 Supported Image Formats

SkiaSharp supports the following image formats:

• PNG (default output format)
• JPEG / JPG
• GIF (including animated)
• WebP
• BMP
• ICO
• WBMP

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🛠️ API Reference

SkiaSharpImageOptimizer

public class SkiaSharpImageOptimizer : IImageResizer { /// <summary> /// Resizes an image from the input stream to the specified dimensions /// </summary> /// <param name="inputStream">The input image stream</param> /// <param name="newWidth">The target width (absolute value will be used)</param> /// <param name="newHeight">The target height (absolute value will be used)</param> /// <returns>A new stream containing the resized image in PNG format</returns> Stream ResizeImageFromStream(Stream inputStream, int newWidth, int newHeight); }

Extension Methods

// Recommended method public static UploadServiceConfigurationBuilder UseSkiaSharpOptimizer( this UploadServiceConfigurationBuilder builder); // Deprecated method (backward compatibility) [Obsolete("Use UseSkiaSharpOptimizer instead")] public static UploadServiceConfigurationBuilder UseImageMagickOptimizer( this UploadServiceConfigurationBuilder builder);

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🧪 Testing

The package includes comprehensive unit tests:

• Valid image resizing
• Negative dimension handling (converts to absolute values)
• Invalid stream handling
• Various dimension scenarios
• Large image handling
• Output format verification (PNG)

To run tests:

cd src/UploadService/DotNetBrightener.UploadService.ImageOptimizer.Tests dotnet test

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📊 Performance

SkiaSharp provides excellent performance characteristics:

• High-quality resizing with SKFilterQuality.High
• Native code execution via Skia engine
• Efficient memory usage with proper disposal patterns
• Cross-platform optimization for each OS

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🐛 Troubleshooting

"Failed to decode image from input stream"

Cause: The input stream doesn't contain a valid image or format is not supported.

Solution: Verify the input stream contains valid image data and is in a supported format.

"Failed to resize image"

Cause: Invalid target dimensions or corrupted source image.

Solution: Ensure width and height are positive integers and source image is valid.

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🔗 Dependencies

• SkiaSharp (3.119.1 or later) - Main graphics library
• Microsoft.AspNetCore.App - Framework reference
• DotNetBrightener.SimpleUploadService - Upload service abstractions

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📜 License

This package is part of the DotNetBrightener Framework.

© 2017 - 2025 Vampire Coder (formerly DotNet Brightener)

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🆘 Support

For issues, questions, or contributions:

• GitHub Repository: https://github.com/dotnetbrightener/dotnet-brightener-framework
• Issues: https://github.com/dotnetbrightener/dotnet-brightener-framework/issues

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📚 Additional Resources

• SkiaSharp Documentation
• DotNetBrightener Framework Documentation
• CVE-2025-65955 Advisory