The one I'm currently using is one I made. It's okay, but I have been thinking of updating it to better reflect me; if that makes sense.
The result I got from this was really nice and reflects me a lot better than my current picture. I might try to make a new logo, using the image from this as a reference, but I'm struggling for time to make one with me doing a MSc.
Essentially, I'm not confident that my own skills are enough to make a good profile picture.