Masking a Graphic in a Movieclip

Hi
I am doing startdrag and stopdrag on graphics.
The graphics are transparent png and converted to MC format.

and currently my startdrag function are moving the whole box of selected graphic (the person including the transparent space around it) instead of just the person.

so how do i go about? when i can’t select just the person?

my apologies because i’m not that great in flash and i do not know what to search about.
i have tried createasbitmap or masking but i don’t really understand em.