Browser use Caching for file that is mostly chanced to use again as resources on page.
When you visit any site chrome download these file from http server and cache for you inside the browser. it will help them to make less load on server and loadtime on client side browser.
You can see those file’s list at chrome://cache/ open this url in browser’s omnibar and you will got the list of cached file from the site that you currently have visit.
If you use chrome dev tool on any site you can see those file in network tab. the good thing is you can download the image,mp3 file if you like to have them.
The one way to access the file is when you use the site then open the tool and go to network tab. You can see a lot of file their when they requested on the page. You can click on it and got the file (one way).
The second way is the one that I show you earlier (chrome://cache open it in browser).
Cheers, You can enjoy this trick on site that use html5 or sometime play music on it. You can got it and put them on your device if that sound pretty cool.