Image viewer for macOS

Hold the arrow key. Kuk keeps up.

Kuk is a free image viewer for the Mac, made for going through big folders of photos. Thumbnails come from the cache Finder has already built, images decode off the main thread, and anything you skip past is cancelled before it costs you time.

Download for Mac

Version 1.7.0, 2.4 MB. Needs macOS 26 Tahoe or later. Open source under MIT.

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A working model of the app, drawn in the browser.A working model of the app. Tap a photo to select it, double-tap for fullscreen.Click it, then try:

  • ←→↑↓ move
  • Space fullscreen, again for slideshow
  • P pick
  • X reject
  • U clear
  • Esc back

01 / Browsing

Made for folders with thousands of photos

Kuk loads the images around your selection before you get there and drops any work that scrolls out of view. Holding → through a big folder never builds up a queue: you see the photo you stopped on, not the fifty before it.

  • Thumbnails come from QuickLook, the same cache Finder uses, with an ImageIO fallback.
  • Photos are decoded at the size of the viewer. Full resolution only when you zoom in.
  • RAW files open from their embedded full-size preview. The raw data is developed only when you zoom in.
  • Jump to the next folder with images with ⌥⌘↓, or up to the enclosing folder with ⌘↑.
  • Files added or removed in Finder show up on their own.

02 / Culling

Go through a shoot in one pass

Press P to keep a photo, X to reject it, U to change your mind. Filter the grid down to your picks, copy or move them to a new folder in the background, and send every reject to the Trash at once. The Trash has undo.

  • Flags are saved as green and red Finder tags, so they survive quitting, travel with the files and show up in Finder and Spotlight.
  • Flags work in the grid and in fullscreen.
  • Select with ⇧ and ⌘ clicks, or switch on Selection Mode with checkboxes.
  • Share, convert, rename and trash act on the whole selection.

03 / Viewing

Everything the file knows about itself

The info panel reads EXIF: camera and lens, ISO, shutter, aperture, focal length, and GPS with a link to Maps. Photos open fit to the window. Pinch to zoom, double-click for 100 %, rotate with ⌘L and ⌘R without re-encoding.

  • Space opens fullscreen, Space again starts a slideshow with an adjustable interval.
  • Animated GIF, APNG and WebP play, and EXIF orientation is always respected.

04 / And also

The rest of the toolbox

Convert
Batch convert to PNG, JPEG, HEIC, TIFF, WebP, GIF or BMP with adjustable quality.
Rename
One file, or many with a numbered pattern: Trip-### becomes Trip-001, Trip-002 and so on.
Apple Photos
Browse All Photos, Favorites, Recents and your albums from the sidebar, with your edits. Read-only, your library stays untouched.
Finder
Drag folders in and images out, use Open With, or make Kuk your default image viewer.
Folder tree
Keep several folders open at once, each with its subfolders and image counts. Subfolders can also show up as tiles in the grid.
Search and sort
Find photos by what is in them (dog, beach, car) or by text in the photo, in one folder or everywhere. It runs on your Mac. Plus eight sort orders including Date Taken.
Updates
New versions are offered and installed from inside the app.
Languages
English and Czech.

05 / Keyboard

Everything has a key

The ones you'll use every day. The full list is in the menus and in the README.

Browse

  • ←→↑↓Move selection
  • HomeEndFirst / last image
  • SpaceFullscreen
  • EscLeave fullscreen / close photo

Folders

  • ⌘OOpen folder
  • ⌥⌘↓⌥⌘↑Next / previous folder
  • ⌘↑Enclosing folder

Cull

  • PPick
  • XReject
  • UClear flag
  • ⌫Move to Trash
  • ⌘ZUndo trash

View

  • ⌘+⌘−Zoom in / out
  • ⌘1Actual size
  • ⌘0Zoom to fit
  • ⌘L⌘RRotate

Files

  • ⇧⌘EConvert
  • ⌘⌥RRename
  • ⇧⌘CCopy image
  • ⌘⌥SShare
  • ⇧⌘RShow in Finder

06 / Install

Two ways to get it

Homebrew

The cask removes the quarantine flag, so Kuk starts without a Gatekeeper prompt. Updates come through the app or brew upgrade.

Direct download

  1. Download Kuk-v1.7.0.zip and unzip it.
  2. Move Kuk.app to your Applications folder.
  3. Kuk isn't notarized, so macOS blocks the first launch. Open System Settings, go to Privacy & Security and click Open Anyway. You only do this once, updates install without it.
Download Kuk 1.7.0All releases ↗

Requires macOS 26 Tahoe or later.