Hi Bill,
Thanks for getting in touch!
The Events Calendar, by default, will not display either an image or an image placeholder if any image is not entered for an event. In other words, it looks like the theme you are using is adding those gray placeholders in there.
If you send me a link to where I can see those placeholders, I’d be happy to try providing some CSS to help hide them. At the same time, I would also recommend reaching out to the theme author for help removing them altogether since those areas still technically load with CSS, even if they are hidden, and the theme author will be able to help make that change.
Thanks!
Geoff