Lossy PNG compression for macOS — reduce file sizes by applying lossy compression to the alpha channel.
- Lossy alpha compression powered by pngquant/libimagequant
- Real-time preview — see before/after as you adjust settings
- Adjustable colors and dithering for fine-tuned control
- Side-by-side comparison — split view with draggable divider to compare original and quantized
- Copy & drag export — Cmd+C to copy, or drag the image directly to Finder or other apps
- Background previews — checkerboard, solid color, and image textures
- File size savings displayed before saving
- Open With support — right-click any PNG in Finder to open in ImageAlpha
Pre-built binaries are available on the Releases page.
- Xcode 16+
- Rust toolchain (
cargo) — install via rustup.rs
git clone --recursive https://github.com/bensquire/ImageAlpha.git
cd ImageAlpha
make pngquant # build libimagequant (Rust)
make release # build the app (Xcode)The built app will be at ~/Library/Developer/Xcode/DerivedData/ImageAlpha-*/Build/Products/Release/ImageAlpha.app.
To create a distributable DMG:
brew install create-dmg
make dmg- Kornel Lesiński — original ImageAlpha author
- pngquant and libimagequant — the quantization engine
- ManyTextures — tileable background images
This project is licensed under the GNU General Public License v3.0.