Source for character expressions

Hi all, I'm very new to Storyline and I'm having a blast.  I love the stock photo characters in a million different facial expressions and moods, but I need more for a course I'm doing and Storyline doesn't have what I need.  I've also checked out the eLearning Brothers package, but that won't let me buy photos a la carte, and regular stock photo sites like istockphoto, ThinkStock, and such, but they just don't seem to have many choices when it comes to expression change photos for this type of thing.  There is a range of happy to neutral expressions, but nothing that shows a person's wide range of emotions. Any advice for a good source of emotion photos? Specifically, I need doctors, but not doctors wearing masks and operating room clothing.