Changing the position of an image inside another image

I need your help please. I'm working in Matlab and I have tow images one with size 256*256 and the other one with size 64*64. I want to embed the small image into the first one but i would like to control the position of the embedding process. For example having the small image in the corner of the big image and then I want to change it in the middle ... do you have any idea how ? thank you