Question(s) about Shutterstock Licensed Images

[kkimsey1]

Okay, I have a few questions that I'd like clarification on, if at all possible! A note to make it easier: I format books for people using Vellum. 

1: I have added an option to my formatting gig that adds a licensed image (for heading images or ornamental breaks). Along with this, I have added the option to add an additional image (in case they'd like the other from what they picked originally). My question is, I have a client that ordered that package, and grabbed the extra licensed image as well. Originally this was fine, but I realized their format doesn't actually have scene breaks in it, meaning they only need the one image. 

Do I have to select an image since they ordered it? If I don't select one, will it just level out and they won't be charged for the image I didn't select? Or do I need to do something to get rid of that extra option for them (and if so, how)? Sorry, I just want to make sure I'm going about it right. 

2: My second question is relating to the same thing. I have multiple recurring clients who want to use the same images across all their books. Can I continue using the one they ordered in the first order, or do they need to pay for that image for each individual format? 

I hope that all makes sense! Thanks :)!