Featured image – size; Lightbox on all images

Hello,

Yesterday I purchased Aegaeus and now I’d like some help configuring some specific aspects.

First, I noticed that the size of featured images displayed in, say, a category, has changed (as compared to the default TwentyTwelve theme). How do I set a size that fits better with my content?

Secondly, is there an option NOT to display the featured image on top of the content after opening a particular post?

And finally, if featured images in a post open in a Lightbox, why don’t normal inline images do so as well? Any way to add this functionality without resorting to a plugin?

Thank you!