The title says it all. Hold down Ctrl and move your mouse wheel up or down to enlarge or shrink your icons in Windows Explorer. When you right click an area of empty space in a Windows Explorer window, you are only given 3 different sizes to choose from.
However, the mouse wheel gives you the flexibility of 28 different sizes (Yes I actually counted each click my mouse wheel made.) This can come in handy for those with overcrowded desktops or if you are enthusiastic about different icon sizes.
Source:→ VistawiredMicrosoft, Windows Vista, Resize, Icons, Quickly, Mouse, Wheel, Mouse Wheel, Resize icons, Tips