Are you talking about these icons?
If so they are in the DDORes.dll in both C:\Windows\System32 and C:\Windows\SysWOW64 for 64-bit
You should work on copies of the .dll on your desktop using a resource hacker of some kind. After you have made your changes you will need to take ownership and give yourself permission so you can rename the old .dll and replace it with the new one
look at post #6 in this thread and it will tell you how Basic Networking Information
if you need more info or help let me know.