Bootstrap 3.为每个屏幕大小添加不同的导航栏品牌图像大小

I have a perfectly fine Bootstrap 3 website. Every page contains a navbar-brand class and a normal navbar. I used the navbar-brand class to display a logo on my website. It works fine in the major browsers and on extremely large screen sizes(beamer/projector) and normal desktop/laptop/tablet screen sizes. I have a perfectly fine Bootstrap 3 website. Ev