Image align to center

Hello.
I would like to center image when the website viewing by a smartphone.
I am using the image effect in a custom code module.
Thank you in advance.

Hi
please give me your url to check the problem
CEd

terzis-ilektrologika.gr/

ok, in your editor where you have placed your images, just add a text-align:center on the parent paragraph (you can do that easily with the button of your editor)