The Mac OS let you modify the existing icons any non-system file, folder, or volume. These are called custom icons. They are saved into a file's resource fork, and an attribute bit is set to alert the Finder to display a custom icon. Folders and volumes do not have resource forks, however, so custom icons are saved instead to an invisible file named ICON. This file is located at the root level of the folder or volume.
Creating a Folder That Uses a Custom Icon
Follow these steps to create a folder that uses a custom icon:
1. Select the graphic to use for an icon. An icon in the Get Info window of any document is one possible source. You can also use a graphic application to create your own.
2. Copy the graphic to the Clipboard by choosing Copy from the Edit menu.
3. In the Finder, select the icon you want to change.
4. Choose Get Info from the File menu.
5. Ensure that the Locked box in the lower-left corner of the Get Info window is not checked. You cannot customize the icon of a locked file.
6. Click the icon at the upper-left of the Get Info window or press the Tab key to select it.
7. Choose Paste from the Edit menu.
8. Click the Close box to close the Get Info window.
If the selected graphic is bigger than the icon in the Get Info window, it automatically shrinks to fit.
Deleting Custom Icons
To delete a custom icon, do the following:
1. In the Finder, select the file.
2. Choose Get Info from the File menu. An information window will appear.
3. Click the icon in the top left portion of the window.
4. A rectangle/outline will appear around the custom icon.
5. Press the Delete key to delete the custom icon.
Custom Icon Repair
Sometimes custom icons created for files, folders, or hard disks no longer work or are deleted. If the link between the folder or volume and the ICON file is lost, the Finder may display a generic document icon in place of the custom icon. When attempting to edit this icon through Get Info, you get an error message saying that the item cannot be found. If you have a missing custom icon on a folder, follow these steps:
1. Create a new folder.
2. Copy the folder's contents into the new folder.
3. Drag the empty folder to the Trash.
4. Give the new folder a custom icon by following the steps in the preceding section.