When working on a real project, you might organize your files in a structured way using folders inside other folders. This is what we mean by a nested directory structure.

For example:

website   
│── home  
│   │── index.html
│   │── images  
│   │   │── banner.png 

Here, banner.png is inside the images folder, which is inside the home folder, making it a nested directory structure.

Since index.html is in the home folder, you’d reference the image like this:

This tells the browser to look inside the images folder, which is in the same directory as index.html, to find banner.png.