Hmm... I write about previews. Despite the fact that css spelled out the size of 200px when the page loads load the full image and is reduced to 200px. If the set value is _record_image_thumb record_image, it will load a small preview and adapted to 200px.
Here, as an example, a piece of modified code from the supergrid listing:
<div class="ipsType_right SG_image_container ipsAreaBackground_light" style="padding-bottom: {{if settings.SuperGrid_aspect_ratio}}{setting='SuperGrid_aspect_ratio'}%{{else}}50%{{endif}};
{{if $row->_record_image_thumb}}background-image:url('{{if settings.SuperGrid_image_use_thumbnail}}{file='$row->_record_image_thumb' extension='cms_Records'}{{else}}{file='$row->_record_image_thumb' extension='cms_Records'}{{endif}}');{{elseif settings.SuperGrid_fallback_image}}background-image:url('{setting="SuperGrid_fallback_image_url"}');{{endif}}">