Finder's View Options allow you to control the way your icons look on your desktop and in your folders. You can zoom your icons all the way up to a hefty 128x128 (shown here) or shrink them down to a modest 16x16. There are tradeoffs of course. Smaller icons let you see more files at once while large icons better allow you to preview your files, especially pictures. You can easily experiment with changing your icon sizes as follows.