To create a guild icon:
Select a small picture.
Use Paint to reduce the picture size to 16x11 pix.
Place the icon in your 'My Documents' folder.
Enter the game. Open the Guild page by pressing "g" the click "modific" a window will pop up and ask you to enter the name of the icon file. If you have named file icon.jpg you must enter the entire file name into the box.
So if the files name is icon.jpg type that into the box and press ok. Viola! You now have your new beautiful guild icon.
NOTE: Guild icons can only be applied if they are in .jpg, .bmp or .tga format!