Resizer3 (Multithreaded Image Converter for converting image file formats and Resizing for saving space)
Ultra-Fast Batch Image Converter & Resizer
Process massive image collections in minutes, not hours.
This high-performance batch image converter is built for speed. Unlike most image tools that cap out at just a few threads, this app can fully utilize modern multi-core CPUs and can scale up to whatever your PC can handle for extremely fast conversion and resizing, or downscale for background processing.
Whether you’re processing a photo shoot, preparing images for the web, or shrinking an image library, this tool is designed to get out of your way and finish the job fast.
Key Features
⚡ Extreme Performance
- Highly optimized multithreaded engine
- Processes hundreds or thousands of images fast
- Scales with your CPU core count
🖼️ Format Support
- Convert to JPG, PNG, HEIC, WEBP
- JXL support (experimental)
🎛️ Full Control
- Adjustable output quality (%)
- Adjustable resolution scaling (%)
- Balance clarity vs file size easily
📊 Real-Time Feedback
- Before & after file sizes
- Total files processed
- Live processing speed
🧩 Simple, Clean UI
- Select image files (drag and drop)
- Choose output format and settings
- Click Convert — no complex setup
Ideal For
- Photographers processing large shoots
- Bloggers & content creators optimizing images for faster page loads
- Anyone with a large image library that needs resizing or compression
How It Works
- Select images (drag and drop)
- Choose a destination folder
- Pick output format, quality %, and resolution %
- Click Convert and watch it process in seconds
Performance Notes
Processing speed depends on your system hardware. The biggest factors, in order of importance:
- CPU: more cores/threads = faster processing
- Storage speed: NVMe SSDs perform far better than HDDs or USB drives
- RAM: large images + high thread counts increase memory usage
- GPU: no impact (CPU-only processing)
Image Format Recommendations
- JPG: best compatibility, good quality/size balance
- HEIC: excellent compression, limited compatibility on some systems
- WEBP: modern, widely supported, great quality/size balance
- JXL: experimental, slower, use with caution
Important Notes
- Always keep source and destination folders separate to avoid overwriting originals.
- Requires Microsoft .NET 10.0 Runtime (installer will prompt if missing).
About This Project
This tool started as a personal hobby project after struggling to find an image converter that could truly take advantage of modern multi-core CPUs. It’s still actively used and maintained, with updates and fixes released as time allows.
Support is best effort.