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Card layout feels to crowded with 3 columns:
- Remove one column and use 2 columns layout: that will let images shine. 
- Update image aspect ration to 16:9 or 1200x630 ratio that is standard for social sharing. (OG) You can pull same image for social sharing of discussions or posts synced. (You created a unique way for events already) 
I did an ugly drawing showing the idea: https://share.zight.com/E0ueG7Og
Thank you!