how do I chage card size on solitaire?

Answer 1

if you are playing the game that came with windows,expanding page is all you can do.they don't get bigger.

Answer 2

Selecting small table before you enter a room makes more room for dialog on table.
Selecting small table after you enter does too, and also stops the ads, however; you only see the top half your cards.
Or you can just change your screen resolution by going to properties on your desktop, then settings and slide just a tiny bit from 800x600 to 1024x768 and switch it back when you finish playing. Which is what I do.