Display 3 pictures on product page

I want to display 3 pictures on the product page. I works well for the main pictures but the 2 others under the mail are too much small (20px -20px) I tried to resize thumbails with config>files but hit didn't work. Does someone has an idea ?
Thanks

well, I changed size of these thumbnails on product page through frontend_custom.css file by altering:


div#hikashop_product_right_part img.hikashop_child_image{
margin : 2px;
height:50px;
}

Thank you very much. I works !