To solve the problem of addons not loading native Joomla images in articles, it is quite simple.
Open templates/newsberg/sppagebuilder/articles_addon/site.php
Change this:
if(isset($image) && $image) {
$output .= '<a class="sppb-article-img-wrap" href="'. $item->link .'" itemprop="url"><img class="sppb-img-responsive" src="'. $image .'" alt="'. $item->title .'" itemprop="thumbnailUrl"></a>';
with this:
if(isset($item->image_thumbnail) && $item->image_thumbnail) {
$output .= '<a class="sppb-article-img-wrap" href="'. $item->link .'" itemprop="url"><img class="sppb-img-responsive" src="'. $item->image_thumbnail .'" alt="'. $item->title .'" itemprop="thumbnailUrl"></a>';
This variation is to be made in two places, in lines 379 and 525.
This way, if you use your joomla images they will be the ones that will be used in the addon. If you use Page Builder blog images (guess or video), those will be loaded as priority