OK, I've customized the icons to my satisfaction (with the exception of the Loader in the system tray but I'm not bothered about that). For the record, here are my notes:
K-Meleon.png is my "original" graphic
KM0.gif is the graphic at 256 colors
From KM0.gif are derived the 16, 32 & 48 px icons
KM3.ico is a multi-icon resource containing the 16, 32 & 48 px icons (see attached file).
Procedure...
Duplicate C:\Program Files\K-Meleon\skins\Phoenity as C:\Program Files\K-Meleon\skins\Custom
Copy KM3.ico to main.ico and overwrite it in C:\Program Files\K-Meleon\skins\Custom
K-Meleon: Preferences > GUI Appearance set the skin to Custom
Windows: Registry:
[HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet\k-meleon.exe\DefaultIcon]
@="C:\\Program Files\\K-Meleon\\skins\\Custom\\main.ico"
Windows: Explorer > Tools > Folder Options > File Types:
URL:HyperText Transfer Protocol = Advanced > Change Icon
URL:HyperText Transfer Protocol with Privacy = Advanced > Change Icon
HTM File = Restore, Advanced > Change Icon, Change > Always use K-Meleon
(HTML File = Restore, Advanced > Change Icon, Change > Always use K-Meleon)
Change other shortcuts using right-click > Properties > Change Icon