This feature was introduced about a week ago, but I noticed that some people have not yet taken advantage of it. Autolinks can now show card previews! If you hover your mouse over a card link, it will popup an image of that card until you move your mouse away. Cards are only loaded when you need them, so it will not use extra bandwidth. Furthermore, you can choose between small, medium, and large (full) sized previews to find the best option for your internet speed and screen size.
Please set your preference by going to:
Profile-->Look and Layout Preferences
Choose your option from the drop down box at the bottom of the screen:
Image preview for [card] tags:
Enjoy!