I just checked your site, the issue you are mentioning above, i guess it seems okay, means images are center aligned.
moreover lalindsey, gives the solution it should work, if you want to centralized your site content.
Please, point out the area where you are facing issue now, and what you want to do with that???? As, after having a look on your site, there are lot of things which i guess, needs bit modification like, footer text color, search bar adjustment.... etc...
One thing more...
The recommended approach to do any sort of modification in any wordpress theme is to create its Child Theme.
For quick example to create a child theme, please click here.