Monoko

A fast, native image viewer for macOS, built for Apple Silicon.

Monoko is designed for quickly opening, reviewing, and adjusting images without the weight of a full photo editor. It uses Metal for rendering, Apple ImageIO for broad format support, and a minimal interface that stays out of the way until you need it.

Why Monoko

• Instant image review — open an image and move through the folder with the arrow keys.
• Native Metal rendering — smooth zooming and panning on Apple Silicon Macs.
• RAW-friendly workflow — supports system RAW codecs and shows embedded previews while full-resolution images load.
• Useful adjustments, not clutter — exposure, contrast, vibrance, sharpness, auto tone, rotation, and mirror.
• Real image metadata — inspect camera, lens, exposure, GPS, color space, and pixel dimensions.
• Made for focus — no library import, no account, no timeline, no extra workflow.

Supported Formats

Monoko uses Apple ImageIO, so it supports the image formats available on your macOS system, including JPEG, PNG, HEIC/HEIF, TIFF, GIF, BMP, WebP, ICNS/ICO, and RAW formats such as DNG, CR2, NEF, ARW, RW2, and more through Apple's system RAW codecs.

Getting Started

Open an image with Monoko from Finder:

1. Right-click an image.
2. Choose Open With -> Monoko.
3. Optionally set Monoko as the default image viewer.

You can also launch it from Terminal:

open Monoko.app --args /path/to/image

Or run the app executable directly:

Monoko.app/Contents/MacOS/Monoko /path/to/image

Controls

Input	Action
Scroll	Zoom at cursor
Double-click	Toggle fit / actual pixels
Drag	Pan
← / →	Previous / next image in folder
0	Fit to window
1	Actual pixels
2 - 9	Zoom to 2:1 ... 9:1
Tab or ⌘A	Toggle Adjustments
⌘I	Toggle Image Info
Esc	Exit fullscreen or fit to window
⌃⌘F	Toggle fullscreen
⌘Q	Quit

Adjustments

Open the Adjustments panel with Tab or ⌘A.

Monoko includes lightweight, non-destructive session adjustments:

• Exposure
• Contrast
• Color / vibrance
• Sharpness
• Auto tone
• Rotate left / right
• Mirror
• Reset

Adjustments are remembered while you browse during the current session.

Image Info

Open Image Info with ⌘I to inspect metadata such as:

• Camera make and model
• Lens
• Date and time
• Shutter speed, aperture, ISO, focal length
• GPS coordinates
• Color model and bit depth
• Pixel dimensions

Build From Source

Requirements:

• macOS
• Xcode command-line tools
• Metal Toolchain component
• Git submodules

Install prerequisites:

xcode-select --install
xcodebuild -downloadComponent MetalToolchain

Clone and build:

git clone --recurse-submodules git@github.com:pinebit/monoko.git
cd monoko
make

Useful commands:

make        # build Monoko.app
make run    # build and launch
make clean  # remove build output

Technology

Monoko is intentionally small and native:

• Metal / MetalKit for rendering
• ImageIO for image decoding and metadata
• Cocoa for macOS integration
• Dear ImGui for lightweight panels

License

MIT. See LICENSE.