You can't directly convert PNG into SWF. PNG alone would look like an already made hair/costume/character, as a whole. The way SWF imports for this game work is that they have many multiple layers, for hands, for arms, for one leg, for the other leg, for chest, for back which aren't put in a single 'plane' so to speak so you'd have to have them all separate. If you'd want to cut different parts of PNG into it, you'd still need to draw some pieces yourself since there are different states of character and one png wouldn't capture all of the states. (Hand position, body movement, breast sizes). Even if you did cut an image into those multiple layers, they would look pixelated since they're not vector graphics (as in, they lose quality when resolution is changed), so you would still need to draw an actual stuff yourself, using your png as a reference at most.
If you want some image made into swf, you could request it.