need help in node_image and i18n module

Hi all
I need help in adding drupal node_images and i18n module in my theme. I installed them into my module folder and enabled them. Now I need further help. How language will change according to click on the flag images. For doing this, do I need to add anything in template.php file ?? Another major problem is how can I change images using node_image module according to my interaction. Any specific link might help for me as I am new drupal themer.

Thanks in advance.