2 general questions about customizing G2

Hi,

I am in the process of creating my own website, and I want to integrate g2 into it. As I started messing with the matrix theme, I realized that I want to get rid of some of the sidebar options (and move it the bottom portion of the screen), as I struggled with this a bit, I slowly got the impression that I may be better off creating my own custom theme (which would be very similar to matrix, minus some features, with some things removed (like the sidebar for users logged in as guest).

So thats my first question, to make the changes I described above, should I create my own theme?

On to my second question. The way my site is setup, my pictures are on a subdomain (i.e. pics.mysite.com), where as the rest of the content is found at mysite.com. I want to somehow incorporate the 'Random Image' into my main site. I was wondering if there is a way to query g2 for a random image? which I could change either on a reload or through javascript?

thanks in advance for your help!