Whether you are trying or not, you are projecting an image when you are playing a live show. You are making the choices: t-shirt and jeans, a skirt (how long or short?), formal wear, outrageous wear. Whatever it is, everything that you do is a part of the overall experience. Like it or not, we live in a society that is based on image. People will look at your band on stage: your clothes, your equipment, any stage decor (if you have a banner hanging up or projected image) and automatically make some conclusions about you even before you begin.
It’s important to provide a consistent, cohesive message. It’s also great if that same image is exciting, edgy, or surprising. It makes you stand out…and standing out is what makes you remembered. So go ahead, dress to kill. And make sure your merchandise, your artwork, anything associated with your “brand” is out there exceeding expectations as well.