This might be due to:
- The screen resolution and size. For what we recommend checking it in a larger display.
- The Lack of Title and Subtitle. That will remove the white space needed to center the image
- The image not uploading. This is probably a problem wit the server for what we recommend to contact your hosting provider and ask for support or try the solution in this tutorial https://showthemes.zendesk.com/hc/en-us/articles/201481852 as sometimes it helps.