IcoFolder

IcoFolder is a simple-to-use application that enables you to change the icons of your folders. It implements basic options that can be tackled even by users with little or no previous experience in such software.

Old application for replacing icons

Before proceeding any further, you should know that it hasn't been updated for a very long time and, although it can still be installed (be careful not to overwrite the newer DLLs), it no longer works on current Windows editions. We're talking about a tool older than Windows XP.
IcoFolder adopts a user-friendly interface represented by a single window that reveals all options supported by the utility, putting a file browser at your disposal for locating the folder whose icon you want to swap.

How it works

In the following step, all you have to do is point out the full path to the new icon file you're interested in, provided that it has the .ico format. The image can be previewed in the main app window and modifications can be applied with one click. Apart from the fact that you can consult a help manual as well as clear the icon if you change your mind and want another one, there are no other notable options available here.
Taking into account the age of this small-sized software program, it's no wonder that it doesn't contain richer options and doesn't make room for customization. For instance, it doesn't support batch processing, so you can replace the icon of one folder at a time.

Conclusion

This goal can be just as easily accomplished by accessing the Properties dialog of a directory. Moreover, it doesn't offer support for other image files apart from .ico. You should resort to a newer program than IcoFolder for swapping icons.