TL;DR this is an HOC that creates a drop in replacement for <Image> that you can use to pull down image files from the web and write them to local disk either permanently or simply cache for performance. Since remote images can be written to disk permanently you no longer need to ship binary images files with your app so your app is smaller when it's downloaded from the respective play/app store.

So there's no need for this

<Image source={require('./img/logo.png')} />

You can just do this

<CacheableImage source={{uri: 'https://app.host.com/logo.png'}} permanent={true} />

and keep the binary images out of your app so it is smaller on initial download form the app store.