oi-optimize

Fast image optimizer CLI — compress, resize, and convert JPG, PNG, WebP, AVIF, TIFF, and GIF in bulk. Powered by sharp with mozjpeg. Zero config.

A simple, zero-config command-line tool for bulk image optimization. Point it at a file or folder, and it will compress, resize, and/or convert every image it finds — recursively — with a single command.

Features

• 🗜 Compress JPG, PNG, WebP, AVIF, TIFF, and GIF with tunable quality
• 🔁 Convert between formats in one pass (e.g. JPG → WebP, PNG → AVIF)
• 📐 Resize with aspect-preserving fit (no enlargement)
• 📂 Recursive — walks directories and processes every image
• 🚀 Fast — built on sharp with mozjpeg encoding
• 📊 Reports savings — shows before/after size and percentage saved
• 🧰 Zero config — sensible defaults out of the box

Installation

Install globally with npm:

npm install -g oi-optimize

Or run ad-hoc without installing:

npx oi-optimize ./images

Usage

oi <path> [options]

<path> can be a single image file or a directory (walked recursively).

Options

| Flag | Description | Default | | --- | --- | --- | | -q, --quality <1-100> | Output quality | 80 | | -f, --format <fmt> | Output format: original, jpg, png, webp, avif, tiff, gif | original | | -s, --size <WxH> | Resize to width × height (keeps aspect, won't enlarge) | — | | -d, --delete-original | Delete source files after converting to a different format | false | | -h, --help | Show help | — |

Examples

Optimize every image in a folder with defaults (quality 80, keep format):

oi ./images

Stronger compression — quality 60:

oi ./images -q 60

Convert everything to WebP:

oi ./images -f webp

Convert to AVIF and delete the original files:

oi ./images -f avif -d

Resize and convert to PNG at quality 90:

oi ./images -q 90 -f png -s 800x600

Optimize a single file:

oi ./hero.jpg -q 75

Supported formats

Input: jpg, jpeg, png, webp, avif, tiff, tif, gif Output: same, plus cross-format conversion.

How it works

oi wraps sharp with opinionated encoder settings:

• JPEG → mozjpeg (better compression than stock libjpeg)
• PNG → compression level 9, effort 10
• WebP / AVIF / TIFF → quality-tunable lossy encoding
• GIF → passthrough

Resizing uses fit: "inside" with withoutEnlargement: true, so small images are never upscaled.

Files are written atomically through a temporary .oi_tmp file, so an interrupted run won't leave corrupt output.

Requirements

• Node.js ≥ 18

License

MIT © Rubel Hossain