def convert_image_name(cur,imgNum):
    """
    Converts imgNum to image file name without extension, as used in adjacency2 table

    Parameters:
    -----------
    cur : MySQLdb cursors
    imgNum : str
        IMG_Number field entry for table image
    """
    sql = ("select IMG_File "
            "from image "
            "where IMG_Number = '%s' " %(imgNum))
    cur.execute(sql)
    return cur.fetchone()[0].split('.')[0]