XBM for two-color X bitmap format
XPM for multicolor X pixmap format (the default)
Choose Save from the File menu.
If the icon is unnamed or you choose Save As, Icon Editor prompts you for a file name. Type the name and then click Save.
If you save an icon in XBM format that has transparent color in it, an icon mask file is also saved. The icon mask file is named basename.size_m.format. If you move the icon you saved to another folder, you must also move the mask file.