I often relate this business to sports, which is funny considering I am not a sports fan but it does fit... You do not show up dressed up in football gear for swimming lessons. Sounds like common sense, right? Do what your asked and show up in the swimsuit. If you are unsure, ask. I try to give the client what they ask, sometimes that means leaving models out that have pictures are less than professional. That may seem unfair but in the end it is my reputation being put out there.
The other thing to consider...my client, isn't just "my client". They are the client of at least 3-4 other agencies. After being passed over on a couple of jobs, I asked my client for a little guidance...my client talked to me about the snapshots and need for pictures showing joy and happiness, then shared with me the 50+ models from one agency. That was just the girls, all had beautiful pictures, which was no surprise.
Modeling is more than having your picture taken it is a job. If you are lucky enough to land the first job you need to start all over again marketing yourself for the next. The photos I send out on your behalf are the first thing clients see amongst over 200...just like a resume. It will be your first cut.
So, how are you showing up to swim class? It is sink or swim time.