Don't think you are alone on that idea! Most people look at themselves in an over-critical manner - sort of feeling that they don't look as good in the mirror / or public as they imagine themselves to be. However the reality is that you are the only REAL critic because everyone else who sees you and sees your picture NEVER sees any difference between the two except if you are acting silly or whatever isn't normal for you.
So: Be sure you use those other tourists with cameras around their necks to take your picture when you are traveling AND you can return the favor for them - it's a great way to meet new people too!!