replace layer/img in a group

I would like to replace on of my characters’ head as I have a better drawing of it now. I’ve tried importing the new png but I can’t figure out how to get it into the group with the rest of his body parts and his skeleton. I’ve tried dragging and creating an import layer- neither worked. This seems like a pretty simple problem but I’m stuck. I’ve already created an animation with other elements in the scene but not him.

Ok, I think I’ve figured it out, although it was not intuitive, to me. I imported the new img. Then I had to cut the group that it came in in and paste it into his group by highlighting any of the layers in his group and selecting paste. Then I could delete the old head and attach the new on to the skeleton.