How do I change the icon used by my gadget?
When you add a new gadget to the sidebar (by right-clicking and selecting “Add Gadgets…”), Windows Vista displays an icon for it.
This icon is controlled by your Gadget.xml file:
The icon should be 48 pixels wide and 48 pixels hide. You’ll normally use a .PNG file. As you can see from the above screenshot, I took the normal icon and recoloured it (in Paint.NET) slightly to demonstrate.