Very easy 5 minute css job

I am stuck with something which I'm sure it's very easy (I'm a good designer but I am terrible with code). I have recently designed my home page but the main image which I just want to appear in the home page is appearing in all pages. I want someone who makes it appear only in the home page (without ruining any of my design) Please check images to see what's going on. I'm sure someone with good knowledge can easily do this in 5 minutes. I have an idea of what I need to do but I'm not sure where and I rather get some help. In the images you can see the home page which is just how I want it to be, and the other pics are examples of what's happening with the image.