The key is in finding the right combination of features to set you apart from your competitors. We remember the story of the guy in the mall whose neighbors on both sides were having their annual sales. Your marketing identity niche should be wide enough that it will capture the biggest number of customers and narrow enough so that you have no immediate competitors. If you are successful you will have competitors soon enough, and you'll have to reset your niche to eliminate them. We want you to note that, in the previous paragraph, we used the word identity niche, not image niche.
Image implies a false representation.
Nothing upsets buyers more than buying a product or service and discovering that it didn't live up to the marketing claims. When you carve out your niche and declare it, make sure it's an accurate projection of your true identity. You may only cater to older women or to young kids. Your niche may be a combination of all of these factors and more. The important thing is to make your niche big enough to get a lot of customers from your territory, and small enough to eliminate any competitors.