focus stack

I recently saw a fabulous macro image of an insect that apparently had been captured hand held. I asked how it was done and the op said that he swayed slightly to achieve this capturing approx 20 images to focus stack. Is this possible accepting that the overall size and proportions of the image...

We have just bought a little TZ100 and from all the literature it points to being able to Focus Stack in the camera on macro shots. I can shoot in post focus and choose my focus point but I cannot see anyway to focus stack using the merge function as described on the manual. Would anyone (@woof...