How important is your image? I think it represents everything. When you don't know someone, the first thing you see it's his appearance. It is important to be well-dressed depending on the job you're working, or the event you're going to attend to.
What means having a good image? A good make-up, some pretty clothes, new hair-style? Maybe. But, it's important also how you behave. You must think on what to say on the right moment. With your family and friends you'll discuss about casual things, little secrets and other important stuff or just a simple "hello" and "how you've been doing", but when you are in social circle you need to think why are you there.
What I mean is: there are two types of friends. True friends, and friends that you make for your own benefit. In the second type we could also include co-workers, because when you're working you don't choose who you work with. It all depends on what types of people are there and what type of work you're doing. Some say that your friends are your life, I say that your imagination is your life.
Sometimes we ask ourselves why are people who dress improperly on random occasions. It all depends on what they are thinking of. When you go to sleep at night you're thinking about your dreams, maybe your memories, but somehow you choose to think positively, negatively, bad, good. Maybe you're imagining that you're a super hero and you save people. Or that you are thief and that you steal everything you want and the police never catches you. All this little things actually influence your life.
Paulo Coelho said "When you want something, all the universe conspires in helping you to achieve it" It's like when you're thinking before you sleep, or in the middle of the day about things you could become, it's like wanting something from the universe. And you will get it. If you think about good you'll receive what you need, and what you want. When you're thinking about suffering, accidents, sadness, rain, that's what you'll get. Our thoughts also influence our image. It can be the inner self represented in the outside world. Sometimes it can be tricky because of many reasons, but you'll have to decide for yourself whether you should or shouldn't change your image or your way of thinking.