To add a little to what Marco is saying.
I use Photoshop not to crop people out in a group photo but highlight them.
For Example: Most families in the late 1800's only could afford one photo so they took a family shot. I attached the family photo to the family as Media then with Photoshop Highlight one person (or darken everyone but one) for each person in the photo and add the photo to the person media. This give the entire photo some context showing the person in relationship to others in the family. It can be a lot of work but also can be rewarding.
Photoshop has a procedure for doing this that I saw some years ago with a color photo that you only wanted to make the candle color and the rest of the photo B&W.
EDIT: I don't know of a way to use polygons in FTM, sorry.
I use Photoshop not to crop people out in a group photo but highlight them.
For Example: Most families in the late 1800's only could afford one photo so they took a family shot. I attached the family photo to the family as Media then with Photoshop Highlight one person (or darken everyone but one) for each person in the photo and add the photo to the person media. This give the entire photo some context showing the person in relationship to others in the family. It can be a lot of work but also can be rewarding.
Photoshop has a procedure for doing this that I saw some years ago with a color photo that you only wanted to make the candle color and the rest of the photo B&W.
EDIT: I don't know of a way to use polygons in FTM, sorry.