[tony_sologubov]

Alternatively, you can simply override the skins/default/en/items_list/product/center/list/parts/body/thumbnail.tpl
template using Custom Skin module and hard-code your thumbnail sizes in this piece:

      <widget 
        class="\XLite\View\Image" 
        image="{product.getImage()}" 
        maxWidth="{getIconWidth()}" 
        maxHeight="{getIconHeight()}" 
        alt="{product.name}" 
        className="photo" />

The basic guide about overriding templates is here:
http://kb.x-cart.com/display/XDD/Step+2+-+applying+design+changes