If you want to use the backend instead of changing the css you can just go to
Go to your admin
Admin / Configure / Product Listing
Columns Per Row (change it to 2)
/includes/modules/responsive_classic/product_listing.php
find this line 402
Code:
$style = ' style="width:' . $col_width . '%;"';
replace with
Code:
$style = ' style="width:' . $col_width . '"';
and to enlarge image just go the the stylesheet_zcustom.css
line 2684
find
Code:
@media (min-width: 768px) {
.list-image img {
float: left;
margin-bottom: 0px;
width: 80px;
}
and change the width to your desired size