Loding jpg to an MC within a button state

I have a button named Btn1 then under this button I have another MC under the “up” state called img1.

If I use loadmovie(“btn1.jpg”,“Btn1”);
everything is good.

But if I try:

If I use loadmovie(“btn1.jpg”,“Btn1.img1”);
I get nothing.

What am I doing wrong?