Hi Morgan,
As our themes are built under the GPL license, you're more than welcome to make any changes you want to the theme, so if you want to change it to show different thumbnails and full size images for the posts, you're welcome to do that, the theme itself though doesn't come packaged with that functionality.
That being said, could I perhaps ask that you elaborate one your requirements a little more as this might be a feature that would be worth us adding to the Aqualine theme as an update for a future version! When you do so, could you perhaps point to links on your website as examples as this will make it easier for me to understand the specifics and I might be able to guide you on how to do it.