Yeah, but here, they're pointing out XP oddities with picking icon sizes that are too low in resolution in the taskbar and too high a resolution in the system tray.  Unfortunately, I'm seeing the taskbar pick too high a resolution, which is just weird.  Well, I did see somewhere else that there was a way to send two window messages setting the icon twice, specifying the resolution in the message (Visual C++).  One was sent for the regular icon and the other was sent for 16x16.  Also, I made an edit while you were typing apparently.  I was just letting you know I'm giving up on this.  It was good to cut the boredom, ... I think.

Scott Seligman posted on Thursday, September 04, 2008 10:44 AM
Add the icon to the appropriate members of the WNDCLASSEX structure for
your RegisterClassEx call:

wcex.hIcon = LoadIcon(m_hInstance, MAKEINTRESOURCE(IDI_ICONNAME));
wcex.hIconSm = (HICON) LoadImage(m_hInstance,
MAKEINTRESOURCE(IDI_ICONNAME), IMAGE_ICON,
GetSystemMetrics(SM_CXSMICON),
GetSystemMetrics(SM_CYSMICON), 0);

source