cbz-tools-optimizer

High-performance CBZ optimizer built in Rust — batch resize, compress, and convert images (JPEG/PNG/WebP/AVIF/GIF) inside ZIP/CBZ/RAR/CBR archives, fully offline. CLI for Windows / Linux / macOS. Windows GUI included.

Download

Download the latest release from Releases.

Archive	Contents
`cbz-tools-optimizer-vX.Y.Z-windows-x64.zip`	`cbz-opt.exe` (CLI) + `cbz-opt-gui.exe` (GUI)
`cbz-tools-optimizer-vX.Y.Z-linux-x64.tar.gz`	`cbz-opt` (CLI)
`cbz-tools-optimizer-vX.Y.Z-macos-x64.tar.gz`	`cbz-opt` (CLI)

Extract the archive and run cbz-opt.exe or cbz-opt-gui.exe directly. No installation is required. Linux and macOS archives remain CLI-only.

Why cbz-tools-optimizer?


📦 Storage savings	Significantly reduce file size — real-world result: 9.0 GB → 647.6 MB (-93%) in 1m 35s
🔄 Format conversion	Convert JPEG / PNG / WebP / AVIF in bulk — resize and convert in a single pass
⚡ Speed	Parallel processing across archives and images via rayon, fast image resizing, and native JPEG/WebP codecs
🖥️ Cross-platform	Windows / Linux / macOS — single binary, no install
🎯 Device-ready presets	iPad, Kindle, 4K and more — one flag to optimize for your device
🤖 Script-friendly	Batch CLI with JSON output for automation and pipeline integration
🖱️ GUI included	Windows drag-and-drop GUI — no CLI knowledge required

CLI Usage

Resize

# Basic (default: ipad preset 2048×1536, JPEG quality 85)
cbz-opt input.cbz

# Convert a RAR/CBR book to an optimized CBZ
cbz-opt input.rar

# Multiple files
cbz-opt *.zip

# Kindle preset
cbz-opt --preset kindle --quality 80 --suffix _small *.cbz

# Custom size
cbz-opt --preset custom --max-width 1280 --max-height 720 input.zip

# Specify output directory
cbz-opt --output-dir ./output input.cbz

Format Conversion

# Convert all images to WebP (no resize)
cbz-opt --output-format webp --convert-only input.cbz

# Convert Animated GIF entries to Animated WebP (no resize)
# Animated GIF input is converted to Animated WebP regardless of --output-format
cbz-opt --convert-only input-with-animated-gif.zip

# Convert to AVIF for maximum compression (no resize)
cbz-opt --output-format avif --convert-only *.cbz

# Resize AND convert to WebP in one pass
cbz-opt --preset ipad --output-format webp input.cbz

# Convert PNG to JPEG (no resize)
cbz-opt --output-format jpeg --convert-only input.cbz

--convert-only: skips resizing entirely. Same-format files are passed through without re-encoding — zero quality loss.

Options

Option	Default	Description
`--preset`	`ipad`	Size preset (see table below)
`-W`, `--max-width`	—	Maximum width in pixels (`--preset custom` only)
`-H`, `--max-height`	—	Maximum height in pixels (`--preset custom` only)
`-q`, `--quality`	85	Lossy quality (1–100) — used by JPEG output and resized animated WebP
`-s`, `--suffix`	`_new`	Output filename suffix
`-o`, `--output-dir`	(same as input)	Output directory
`-t`, `--threads`	0 (auto)	Number of threads (0 = half of logical CPUs)
`--output-format`	`jpeg`	Output image format: `jpeg` / `png` / `webp` / `avif` / `original`
`--convert-only`	—	Convert format only — skip resize entirely. `--preset` / `-W` / `-H` are ignored. Same-format files are passed through without re-encoding (zero degradation)
`--resize-filter`	`catmull-rom`	Static image resize interpolation: `bilinear`, `catmull-rom`, or `lanczos3`
`--animated-webp-filter`	`bilinear`	Animated WebP resize interpolation: `bilinear` (fast/smooth), `catmull-rom` (sharper bicubic), or `lanczos3` (highest-detail comparison; slowest)
`--animated-webp-keyframes`	`bounded`	Animated WebP keyframe policy: `bounded` uses the interval below; `disabled` does not force periodic keyframes and ignores `kmin` / `kmax`
`--animated-webp-kmin` / `--animated-webp-kmax`	`3` / `5`	Minimum / maximum distance between animated-WebP key frames (`kmax >= 2`, `0 <= kmin < kmax`, `kmin >= kmax / 2 + 1`)
`--animated-webp-output-policy`	`always-use-encoded`	Animated WebP output size policy: write the high-quality resized result (default), or use `keep-original-if-larger` to retain an oversized source entry instead
`--log-mode`	`cli`	Log output: `cli` / `silent` / `both` / `file`
`--overwrite-mode`	`skip`	Output conflict resolution: `skip` / `overwrite` / `rename`
`--json`	—	Output progress as JSON lines (for scripting and automation)

Size Presets

Preset	Width	Height	Intended device
`ipad`	2048	1536	iPad (default)
`ipad-air`	2360	1640	iPad Air
`ipad-pro`	2732	2048	iPad Pro
`kindle`	1264	1680	Kindle Paperwhite
`hd`	1280	720	HD display
`full-hd`	1920	1080	Full HD display
`four-k`	3840	2160	4K display
`custom`	(manual)	(manual)	Use `-W` / `-H`

Supported Formats

Images

Format	Input	Output
JPEG	Yes	Yes
PNG	Yes	Yes
WebP (static)	Yes	Yes
WebP (animated)	Yes	Re-encoded as animated WebP
AVIF	Yes	Yes
BMP	Yes	Converted to output format
TIFF	Yes	Converted to output format
GIF (static)	Yes	Yes
GIF (animated)	Yes	Animated WebP

Static images are resized and re-encoded using the selected output format and quality settings. Static GIFs are decoded through the GIF-specific path and then use the static pipeline; original keeps an in-bounds static GIF byte-identical, while a resized original GIF is written as PNG because GIF encoding is not included. Animated WebP and animated GIF use dedicated paths that preserve frame timing, loop count, and animation; animated GIF input is converted to Animated WebP regardless of --output-format, except that keep-original-if-larger may retain the source GIF and its original entry name. Animated WebP resize and keyframe behavior can be configured with the corresponding --animated-webp-* options. BMP and TIFF inputs are converted to the selected output format. AVIF is supported as both input and output.

GUI Usage

Launch cbz-opt-gui.exe
Drag and drop ZIP/CBZ/RAR/CBR files or folders onto the window (or use Add Files… / Add Folder…)
Configure options via the ⚙ button and click ▶ Start
A completion summary is shown next to the Start button when processing finishes

Ready	Done

Notes:

cbz-opt.exe is not required alongside the GUI — image processing is built in
Supports English / 中文 / 日本語 (language selector in the menu bar)
Settings are saved automatically to cbz-opt-gui.toml in the same folder

Build from Source

Prerequisites (Windows): Requires the MSVC toolchain (stable-x86_64-pc-windows-msvc).
Install "Desktop development with C++" workload from Visual Studio 2022 (or Build Tools for Visual Studio).
The MSVC linker path is pre-configured in .cargo/config.toml — no Developer Command Prompt is required.

# All crates
cargo build --release

# CLI
cargo build --release -p cbz-tools-optimizer-cli

# GUI (Windows)
cargo build --release -p cbz-tools-optimizer-gui

Contributing

Bug reports and feature requests are welcome via GitHub Issues.
Please use the provided issue templates.

How It Works

Multiple ZIP/CBZ/RAR/CBR files
  └── process archives in parallel
        └── process image entries in parallel
              ├── Static images
              │     └── decode → resize if needed → encode
              │
              ├── Animated WebP
              │     └── animated decode → resize if needed → encode
              │
              └── Animated GIF
                    └── GIF decode → Animated WebP encode

Images already within the pixel-dimension limit are not resized, but are still encoded into the selected output format in normal mode. To preserve their bytes, use --convert-only with the matching output format.
Animated WebP and Animated GIF are processed through dedicated animation paths that preserve frame timing, loop count, and animation.
Animated GIF frames are decoded and encoded sequentially. Animated GIF input is converted to Animated WebP; --convert-only leaves the canvas dimensions unchanged.
JPEG DCT pre-scaling is deliberately conservative: the final target dimensions receive a 20% guard, and only 1/4, 1/2, or full decode are considered so the DCT result does not undershoot the guarded target.
Each archive is processed independently; one failure does not abort others.
Default thread count is half of logical CPUs to avoid saturating the system (override with --threads N).
Output file conflict is controlled by --overwrite-mode (default: skip existing files).
A log file (cbz-opt_YYYYMMDD_HHMMSS.log) is written when --log-mode both or file is specified.
On completion, total file size savings and elapsed time are reported.

Changelog

See CHANGELOG.md.

Third-Party Licenses

See THIRDPARTY_LICENSES.md.

License

MIT — see LICENSE.

Name		Name	Last commit message	Last commit date
.github		.github
cmake		cmake
crates		crates
docs		docs
scripts		scripts
third_party		third_party
.gitattributes		.gitattributes
.gitignore		.gitignore
CHANGELOG.md		CHANGELOG.md
Cargo.lock		Cargo.lock
Cargo.toml		Cargo.toml
LICENSE		LICENSE
README.md		README.md
THIRDPARTY_LICENSES.md		THIRDPARTY_LICENSES.md
rust-toolchain.toml		rust-toolchain.toml
rustfmt.toml		rustfmt.toml

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cbz-tools-optimizer

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Why cbz-tools-optimizer?

CLI Usage

Resize

Format Conversion

Options

Size Presets

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Images

GUI Usage

Build from Source

Contributing

How It Works

Changelog

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cbz-tools-optimizer

Download

Why cbz-tools-optimizer?

CLI Usage

Resize

Format Conversion

Options

Size Presets

Supported Formats

Archives

Images

GUI Usage

Build from Source

Contributing

How It Works

Changelog

Third-Party Licenses

License

About

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