TL;DR
Select a file in Finder, hit Space – instant preview for images, PDFs, videos, code. No app launch needed.
How to do it
- Select a file in Finder – single click (don't double-click).
- Press the Space bar – a preview opens instantly in an overlay window.
- Use arrow keys – flip through multiple files without closing Quick Look.
- Press Space again or Esc – close the preview.
What Quick Look supports
- Images (JPG, PNG, HEIC, RAW) – full-resolution preview
- PDFs – scrollable and searchable
- Videos & Audio – plays right inside the preview
- Code & text files – with syntax display
- Office documents – Word, Excel, PowerPoint, Keynote, Pages
- Markdown – rendered nicely
Why this saves you time
Quick Look renders files at the system level – no app needs to launch. When you're browsing a folder with dozens of files, you find the right one in seconds instead of opening each individually.
Especially handy for sorting through photo folders, checking PDFs, or peeking into config files.
Pro tips
- Select multiple files → Space → arrow keys to flip through them (slideshow-style)
- Full screen: Click the expand icon in the Quick Look preview
- Quick Look plugins add support for extra formats (e.g.,
.webp,.csv) - Works in Spotlight too (Cmd+Space): highlight a result → Space bar