Help: How to change the product image size?

[Mr.ice9x]

Please go to my website at this link:
http://vinhphu.vn/index.php/bom-calpeda/bom-ly-tam-truc-ngang-lien-truc
Im having problem with the product image size, its to small. I searched for this problem on this forum but I still cant solve my problem. They said I have to edit css file but i followed the directory and found nothing.. Im using joomla .20 and VM 2.6.0.
Sorry for my bad english.

[GJC Web Design]

in vm config->config->templates

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