Blank Image on main webcomic page?

[foulshamart]

so i have my webcomic all set up and running, i have it adeded to my menus on my website directory and all that. but i am seeing a blank image place holder and i can't figure out where the setting is to add an image there or remove it from view entirely.

here is a link to the page with the image in question: https://foulshamart.com/the-osrynn-tales-shorts/

how do i get rid of that grey box?