Yes, you can share Cards to the Collaborate tab but not Dashboards and sections of Network Reports.

To share a Card to the Collaborate tab,

- Go to Reports, head to the desired social channel

- Hover over a Card and click on the ellipsis on the top right

- Select Discuss

- You'll be redirected to the Collaborate tab where you can add a message with the Card 

- You can attach an image to this post and also choose who can see the discussion