Change slack images

Using either dashboard subscriptions or a questions alerts, sending to slack I get a horrible preview of the data. It includes a link to go to the question or dashboard but the point of the subscription is so people without an account can see these questions without having to log in. I've currently persuaded where I'm at to trial metabase as a replacement for looker which I hate for numerous reasons, but this is a pretty big one. We have a daily digest like dashboard that everyone looks at religiously. From Looker you essentially get a screen shot of the dashboard. For metabase all I've managed to get is just a compact version of the question. Theres no title, theres only data for the current month. Its pretty awful to look at and not at all helpful. Anyone point me to resources to be able to manage how it looks, alternatively if it's already answered that it just can't be changed?

New viz’s be coming probably on v50