image="image_path"
This attribute is required for buttons, check buttons, radio buttons, menu buttons, and combo buttons. The image attribute is optional for color pickers and is ignored for other item types. The image attribute specifies the path, relative to the Configuration folder, of the icon file that displays on the button. The icon can be in any format that Adobe Dreamweaver can render, but typically it is a GIF or JPEG file format.
If an icon is specified for a color picker, the icon replaces the color picker entirely. If the colorRect attribute is also set, the current color appears on top of the icon in the specified rectangle.
Example
image="Toolbars/images/MM/codenav.gif"