It's a free speech issue. She shouldn't legally be barred from taking that picture and she should be allowed to publish or post it anywhere she likes that will allow her to do so; legally speaking.
That doesn't mean people can't criticize her for it and it doesn't mean an employer, sponsor, event organizer, what have you can't choose to no longer do business with her for doing the photo.
As for her apology, that was only because she suddenly realized this was going to mean a loss of business for her.