Zillah theme: Want to resize logo and see how slider works

I made a nice logo for my site, but I’d just like to increase the size of it.

Also, I have a question about the content slider. Do your posts need to be published in order for new categories to show up in the content slider customization. I set everything up properly. I created new categories for the posts I want on the slider and set the image, but when I try to set the slider to the right category, my new categories do not appear. The only option is uncategorized. I was hoping to see how it all looked before I published posts.

The page I need help with: [log in to see the link]