I have client side ability to change viewing size 800-1200 and the photos are now showing off center to the right is there a way for me to address this so the photos are centered on the page properly?

You will have to modify the CSS of your theme.

okay and I access that under what tab?

There is no tab to change the CSS.

Each theme has one ore more .css files. For instance the Default theme has four. One for each theme "personality". (located in the [i]styles[/i] folder)
It's the .css file you have to modify to change the layout of your theme.