slimg

A fast image optimization tool. Convert, compress, resize, crop, and extend images using modern codecs — available as a CLI and desktop GUI.

한국어

Supported Formats

| Format | Decode | Encode | Notes | |--------|--------|--------|-------| | JPEG | Yes | Yes | MozJPEG encoder for superior compression | | PNG | Yes | Yes | OxiPNG optimizer with Zopfli compression | | WebP | Yes | Yes | Lossy encoding via libwebp | | AVIF | Yes | Yes | ravif encoder; dav1d decoder (statically linked) | | QOI | Yes | Yes | Lossless, fast encode/decode | | JPEG XL| Yes | Yes | libjxl encoder/decoder |

Installation

Cargo (crates.io)

cargo install slimg

Homebrew (macOS / Linux)

brew install clroot/tap/slimg

Pre-built binaries

Download from GitHub Releases:

| Platform | File | |----------|------| | macOS (Apple Silicon) | slimg-aarch64-apple-darwin.tar.xz | | macOS (Intel) | slimg-x86_64-apple-darwin.tar.xz | | Linux (x86_64) | slimg-x86_64-unknown-linux-gnu.tar.xz | | Linux (ARM64) | slimg-aarch64-unknown-linux-gnu.tar.xz | | Windows (x86_64) | slimg-x86_64-pc-windows-msvc.zip |

From source

git clone https://github.com/clroot/slimg.git
cd slimg
cargo install --path cli

Build requirements

Rust 1.85+ (edition 2024)
C compiler (cc)
nasm (for MozJPEG / rav1e assembly optimizations)
meson + ninja (for building dav1d AVIF decoder from source)
Set SYSTEM_DEPS_DAV1D_BUILD_INTERNAL=always to build dav1d from source

Usage

For the full usage guide, see docs/usage.md.

# Convert format
slimg convert photo.jpg --format webp

# Optimize (re-encode in same format)
slimg optimize photo.jpg --quality 70

# Resize
slimg resize photo.jpg --width 800

# Crop by coordinates
slimg crop photo.jpg --region 100,50,800,600

# Crop to aspect ratio (center-anchored)
slimg crop photo.jpg --aspect 16:9

# Extend to square with padding
slimg extend photo.jpg --aspect 1:1

# Extend with transparent background
slimg extend photo.png --aspect 1:1 --transparent

# Batch processing with format conversion
slimg convert ./images --format webp --output ./output --recursive --jobs 4

Desktop GUI

A cross-platform desktop application built with Tauri v2 + React.

Drag & drop file/folder input
Before/after image comparison preview
Batch processing with real-time progress
Configurable quality and format settings

Download from GUI Releases (macOS, Linux, Windows).

Benchmarks

See docs/benchmarks.md for detailed performance measurements across all codecs and pipeline operations.

Language Bindings

| Language | Package | Platforms | |----------|---------|-----------| | Kotlin/JVM | io.clroot.slimg:slimg-kotlin | macOS, Linux, Windows | | Python | slimg | macOS, Linux, Windows |

Library

The core functionality is available as a library crate (slimg-core):

use slimg_core::*;

// Decode an image file
let (image, format) = decode_file(Path::new("photo.jpg"))?;

// Convert to WebP
let result = convert(&image, &PipelineOptions {
    format: Format::WebP,
    quality: 80,
    resize: None,
    crop: None,
    extend: None,
    fill_color: None,
})?;

// Save the result
result.save(Path::new("photo.webp"))?;

License

MIT

Slimg

Install / Use

README