View Mac files quickly with Quick Look
Need to quickly view the contents of a file without opening Word or Photoshop (or any other program)? Just select the file in your Finder and hit the space bar. This will open a preview or “quick look” of your file. Use the up/down arrow keys to cycle through other files in the same directory.
If you want to view multiple files at the same time, select the files and hit the space bar. At the top of the pop-up window you can click back/next to rotate through the files, or click on the index sheet button (four little squares) to view thumbnails of all your selected files at once.
To view images full screen, click on the two arrows in the right corner of the pop-up window. In full screen mode, you can navigate through your files with the arrow keys or click the play button to watch a slideshow.
*This is a feature in OS 10.5 and later. To see which OS you are running, go to the Apple menu and click About This Mac.