Hi @Marius,
Thanks for the feedback! I'm not sure if there is a specific reason that we don't already support this, but it's certainly something we can explore adding. I am moving this topic to our feature requests section! I'm not sure what the timeline would be, so I'm hoping we can find a workaround for the time being. 
Is there any chance a list view would better meet your needs? That way, you could use full size components for each "row." We have a new list view in beta that can handle larger amounts of data (more info here), which could be worth exploring if you've had performance issues with our previous list view.
Otherwise, I'd recommend using expandable rows where larger components such as images can be nested in side the expandable section:
Or, you could have a dynamic image next to the table that is linked to the current row's data:
