This repo is a example demonstrating the use of LWC and third-party API integrations. Third-party in this case is the Unsplash API
You can add this LWC on you homepage and refresh the page to get a random image.
For the Unsplash API, you can create get you access_key as shown in the Getting Started documentation of the Unsplash API. You can store the access_key in a custom setting.