Bug 150347 Support binary stream as preview image.
See 144843. We need model to save binary strame as report preview image. Currently, preview image is an external image. Maybe need a type to distinguish preview image type.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/ReportDesignHandle.java
*/
	public String getIconFile( )
	{
		return getStringProperty( ICON_FILE_PROP );
	}
	/**
	 * Sets the design cheat sheet file path.
	 * 
	 * @param cheatSheet
	 *            the design cheat sheet file path to set
	 * @throws SemanticException
	 *             if the property is locked or not defined on this design.
	 */
	public void setCheatSheet( String cheatSheet ) throws SemanticException
	{
		setStringProperty( CHEAT_SHEET_PROP, cheatSheet );
	}
	/**
	 * Gets the design cheat sheet file path.
	 * 
	 * @return the design cheat sheet file path
	 */
	public String getCheatSheet( )
	{
		return getStringProperty( CHEAT_SHEET_PROP );
	}
	/**
	 * Gets all bookmarks defined in this module.
	 * 
	 * @return All bookmarks defined in this module.