Hi,
Thanks for using the Events Calendar.
Here on the pre-sales forum, I’m afraid we do not provide support. I would ask that you take any support questions across to our wordpress.org forum – our staff scan it periodically and other community members may also be able to help out.
The Events Calendar
Having said that we have this guide to adding the featured image to month view:
https://theeventscalendar.com/knowledgebase/adding-featured-images-to-month-view/
If you have questions about it please post in WordPress.org as we are unable to support the plugins in the pre-sales forum.
Thanks again!