I have done something similarly but for the img on the product page. What I did:
I changed the block that load my img.
In my di.xml:
<type name="Magento\Catalog\Block\Product\View\Gallery">
<plugin name="plugin_block_catalog_product_view_gallery"
type="Namespace\Vendor\Block\Catalog\Product\View\Gallery"
sortOrder="10"
disabled="false"/>
</type>
and i rewrite this block by changing the path of the img like this :
public function getGalleryImagesJson()
{
$product = $this->getProduct();
$imagesItems = [];
foreach ($this->getGalleryImages() as $image) {
$imagesItems[] = [
'thumb' => $this->getBaseUrl().'pub/media/catalog/product/'.$image['file'],
'img' => $this->getBaseUrl().'pub/media/catalog/product/'.$image['file'],
'full' => $this->getBaseUrl().'pub/media/catalog/product/'.$image['file'],
'caption' => $image->getLabel(),
'position' => $image->getPosition(),
'isMain' => $this->isMainImage($image),
];
}
if (empty($imagesItems)) {
$imagesItems[] = [
'thumb' => $this->_imageHelper->getDefaultPlaceholderUrl('thumbnail'),
'img' => $this->_imageHelper->getDefaultPlaceholderUrl('image'),
'full' => $this->_imageHelper->getDefaultPlaceholderUrl('image'),
'caption' => '',
'position' => '0',
'isMain' => true,
];
}
return json_encode($imagesItems);
}
I know is not what you need, but this may help you.