You will need to host static files such as images, CSS, etc. You dan do so in the 'Assets' section of your web version. In this section of the control panel you can configure assets metadata as well. For example you can set a maxAge parameter to configure the way browsers are going to cache the asset.

There is also a builtin filter called lastModified that is also very useful for caching assets as well. Check out this article about the different strategies to cache you assets and avoid unnecessary HTTP requests.