Documentation
Everything you need to know to optimize images fast.
Quick Start Guide
Get up and running in 60 seconds:
1. Add Images
Drag and drop image files or folders onto the File Selection area, or click Browse Files.
2. Choose Settings
Set your output format (WebP, JPG, PNG), dimensions, and compression level. Or select a preset.
3. Preview (Optional)
Click the Process arrow in Preview to test settings on a single image. Click the result to inspect quality.
4. Select Output Folder
Click Browse next to Output Folder to choose where processed images will be saved.
5. Process All
Click Process Images. Done! Check the History tab to see file size savings.
Installation
Download & Install
- Download the latest DMG
- Open the DMG file
- Drag The Transmogrifier to your Applications folder
- Launch from Applications
⚠️ First Launch Security Warning
macOS may block the app because it's not signed with an Apple Developer ID. To bypass:
- Control-click (or right-click) the app in Applications
- Select Open from the menu
- Click Open in the security dialog
- The app will now launch normally (you only need to do this once)
System Requirements
- macOS: 11.0 (Big Sur) or later
- Architecture: Intel or Apple Silicon
- Disk Space: ~15 MB
Supported File Formats
Input Formats
- ✅ JPEG / JPG
- ✅ PNG
- ✅ TIFF / TIF
- ✅ BMP
- ✅ GIF
- ✅ ICNS (macOS icons)
- ✅ ICO (Windows icons)
Output Formats
- WebP - Modern web format, excellent compression
- JPG - Universal format, good for photos
- PNG - Lossless, supports transparency
💡 Tip: WebP typically produces 25-35% smaller files than JPG at the same quality.
Understanding Compression
The compression slider controls the trade-off between file size and image quality:
Minimal Compression
Maximum quality, larger files. Best for print or archival.
Balanced
Good quality, reasonable file sizes. Best for most use cases.
Maximum Compression
Smaller files, visible quality loss. Use cautiously.
💡 Recommended Settings
- Web images: 60-75% compression (WebP format)
- Photography: 20-40% compression (JPG format)
- Graphics/logos: 10-30% compression (PNG format)
Managing Presets
Presets save your favorite settings for quick reuse.
Built-in Presets
High Quality
300 DPI • WebP format • Minimal compression
Web Optimized
72 DPI • 1920px wide • WebP format • Balanced compression
Social Media
72 DPI • 1080×1080px • JPG format • Medium compression
Creating Custom Presets
- Set your desired output format, dimensions, and compression
- Select an output folder (this will be saved with the preset)
- Click the Save button next to the Presets dropdown
- Enter a name for your preset (e.g., "Figma to WebP")
- Your preset now appears in the dropdown menu
Troubleshooting
App won't open (Security warning)
macOS is blocking the app because it's not signed with an Apple Developer ID.
Solution:
- Control-click (or right-click) the app in Applications
- Select "Open" from the menu
- Click "Open" in the security dialog
Images look blurry or low quality
Compression is set too high.
Solution:
- Lower the compression slider (drag left)
- Use the Preview feature to test quality before batch processing
- Click the preview image to inspect full-size
WebP format not working
Your macOS version may not have native WebP support.
Solution:
- Update to macOS 11 (Big Sur) or later
- Use JPG or PNG format instead
Need more help?
Check the app's built-in help (⌘?) or open an issue on GitHub.
Report an issue on GitHub →Frequently Asked Questions
How many images can I process at once?
No artificial limits. The only limit is your Mac's hardware. Processing 20-50 images at once performs best.
Does this work offline?
Yes! All processing happens locally on your Mac. No internet connection required.
Are my images sent to a server?
Absolutely not. All processing happens 100% locally on your Mac. No data leaves your computer.
Can I batch rename output files?
Not yet, but it's on the roadmap! Currently, output files keep their original names with the new extension.