Hey Ana,
Thanks for reaching out!
Implementing the design tweaks you mention is only possible by way of custom coding, which is outside the scope of support we can provide. Please read more on that here → https://theeventscalendar.com/knowledgebase/what-support-is-provided-for-license-holders/
With that being said, I’m happy to try and help get you started with the thumbnails you describe.
To help me do that, I’m wondering the following things:
1. Are you referring to the List Widget? I’m pretty sure you are, but just want to be absolutely certain.
2. Can you please post your site’s complete system information to this thread? Here’s how: https://theeventscalendar.com/knowledgebase/sharing-sys-info/
3. You mention having the featured images showing previously, before the update…can you remember how you were able to achieve that? Did you add custom coding to your site, for example?
Please answer each of these three questions—they’ll help me work on a custom snippet for you and we can go from there! 😀
— George