There's always been some discussion about whether or not portraits are important for the provider profiles. I firmly believe that they are - and I'm happy to see some providers have used the portrait to really market themselves well. Consider these portraits:
What do you think potential buyers would prefer?
So, upload a portrait. Exercise some creativity, but keep it personal and individual. You only have a brief second to impress buyers in the search results and a good intriguing portrait can capture that attention.