Tips & Tricks
If you decide to make your own custom icons, there are a few things to be aware of. First, they come in different sizes according to where they are displayed, such as the desktop, the Start menu, Folders, Drives, and so on.
Icons are measured in pixels, and the three sizes used on Windows XP are 16 x 16, 32 x 32 and 48 x 48. Second, icons use a 32-bit palette, enabling you to use any colour that the eye can detect.
In the past, icons were either opaque (solid), or completely transparent, making them appear as sharp-edged cutouts on the screen. Now, they can gently fade into the background, and you can create subtle shadow effects.
Finally, the default Windows icons are packaged and encoded into the shell32.dll, and many program icons are similarly hard-coded. If you choose to replace these icons, you can either select any of the default icons, or you can add icons you’ve downloaded from the internet or created yourself in an image editor or icon creator. Individual icons have the ICO file extension, while icon groups have the ICL extension.