¡The world is your oyster so express your brand appropriately!
Ostentatious or Conservative
Playful or Serious
All Business or Casual
Your headshot should represent how you approach business. I see experienced agents bring at least two outfits. One outfit is how their current clients see them. The second is that first impression outfit. Sometimes that outfit is the same. ¿Sounds pretty broad right? The goal is to be relatable to your client base.
If you are going to see me once a year then I would bring outfits for all seasons. You may want to send out seasonal marketing and why wear the same outfit? Look at Anh Phoong at Phoong Law and she's an attorney not to be out done :-)
I'd also say pay attention to your skin tone. My only reason: Matching your skin tone may make ya look nude, unless you want that of course.
Unless your broker has a specific branding look for website purposes have fun with this and show off your brand, smile!