They look like they are and if they've been with one or more males in the last month you can probably bet your house on it.
How you proceed depends on what you want to do with the fry and whether or not you have hiding places and/or predators in the tank with them.
My MM platy gave birth to at least 10 fry recently and probably some more which didn't survive the first week because they became snacks for their tank mates.
She looked exactly like your second pic for about two weeks or so before the fry were born.
If you want to keep as many fry as you can, best separate her from other fish and provide a place for the fry to escape to from their mother as soon as they are born.
Good luck with it though