Those package of icons contains icons to replace most of the common icons on your Windows PC.
The big difference between Microsoft's themes and IconPackager is that Microsoft's ones only change a few icons and IconPackager changes hundreds of icons ('My Computer', 'Recycle Bin', Folders, all the way to specific file format icons),...
IconPackager can change nearly every icon in Windows. It can even change icons that most people would think are impossible to change.
Do you want to have a holiday looking desktop with all your icons changed? Download one of the many holiday oriented icon sets. Do you want other on? Download other, it is very easy to customize your icons.
Now you can decide how you want your icons to look.
IconPackager integrates itself in WindowBlinds though you can also use it independently.