Here is a picture of what a hero image looks like on a Card. It appears above the Card title.
Currently, you are unable to change the hero image of a card manually, but this is something that we are working on!
Where did the hero image come from?
The cover photo is automatically pulled from an image from the linked Resource URL of the Card, or scraped from the attached file.
Can I upload my own photo? or take down the cover photo?
Currently, you are unable to customize the cover photo yourself. It is on our radar though to allow you to have the option to either add or omit a hero image.