You can put it anywhere that you want to. You can make it "full sized," or you can make it smaller, and beside another text capsule, or any other kind of capsule.
Let me give you the best single bit of advice that someone ever gave me here on hubpages. You're top capsule should be a text capsule, and ONLY a text capsule. I used to put pictures at the top right of my text capsule, because I thought it made the hub look better.
Maybe it did, maybe it didn't; but what matters is that the top text capsule, just to the right of it, is the PRIME spot for Google adsense ads to be placed. I hope this has been helpful to you.