Once you've uploaded an image using the FileUpload component and saved it, you should see a preview in the component.
To find out if you've misconfigured your app, check for any console errors. 404s or 403s? Read on.
Make sure that the APP_URL variable in your .env file matches the domain you're using to access your app from, including the protocol (http or https). This is usually the problem.
Additionally, if you're using the public filesystem driver, ensure that you have run php artisan storage:link.