* manager: modify background image control logic Signed-off-by: WenHao2130 <WenHao2130@outlook.com> * manager: modify padding Signed-off-by: WenHao2130 <WenHao2130@outlook.com> * docs: update README.md README-en.md README-ja.md Signed-off-by: WenHao2130 <WenHao2130@outlook.com> --------- Signed-off-by: WenHao2130 <WenHao2130@outlook.com>