Okay I am feeling my way here so bear with me, i'm typing as I check things and discover things regarding subscriptions to other users' galleries or images.
Okay so you can delete those messages, if you click on the [18 messages] part it will take you to the messages area and it will also have a link at the bottom where you can delete those messages.
also when you are in your profile area of the gallery you can click on statistics to see if you are subscribed to any of her albums or photos,
I can't see a way of unsubscribing you from her gallery. you have to do it from your profile in the statistics part.
Those images are in her own progressives album so maybe unintentionally you are subscribed to that gallery?
check this gallery is not in the list of subscribed to galleries in your profile statistics too.
click on that and see if it stops sending you emails hun.