Mac and PC versions differ only in gamma; the Mac versions look slightly darker. (Depending on your tastes and monitor setups you may even prefer the "wrong" version).

To view full-sized make sure your browser window is full-screen sized, then click on link with appropriate resolution.
 

Acorn For Mac: 1600x1200 1024x768 832x624 800x600 For PC: 1600x1200 1024x768 800x600	Clouds For Mac: 1600x1200 1024x768 832x624 800x600 For PC: 1600x1200 1024x768 800x600	Cloudy sky For Mac: 1600x1200 1024x768 832x624 800x600 For PC: 1600x1200 1024x768 800x600	Erythronium For Mac: 1600x1200 1024x768 832x624 800x600 For PC: 1600x1200 1024x768 800x600
Herring (Middleboro, MA) For Mac: 1600x1200 1024x768 832x624 800x600 For PC: 1600x1200 1024x768 800x600	Glass cuboctahedron behind windowshade For Mac: 1600x1200 1024x768 832x624 800x600 For PC: 1600x1200 1024x768 800x600	Oil rainbow For Mac: 1600x1200 1024x768 832x624 800x600 For PC: 1600x1200 1024x768 800x600	Trees at sunset For Mac: 1600x1200 1024x768 832x624 800x600 For PC: 1600x1200 1024x768 800x600

Mac users: Click on link with appropriate resolution so you are viewing the picture full-sized.

While viewing, press AND HOLD the mouse on the picture until a menu appears.

choose (Internet Explorer) Download Image to Disk or (Netscape) Save This Link As...

In the dialog box, be sure you notice the location the file is loading into. I suggest you use the directory to direct the Mac to save the file on the desktop.

Make sure you can see the file on the desktop—either directly on the desktop, or in some open window.

Apple menu, Control panels, Appearance

Drag the file to the control panel.

While viewing, press and hold the right mouse button on the picture so that a menu appears.

Choose "Set as background" or "Set as desktop."

Additional search terms and phrases: free desktop pictures, nature pictures, nature photos.