Hi,
Thank you for the deteils. The reason it didn’t work, because there is no featured image, nor any content within those gallery posts whatsoever, so the plugin was not able to get any images from that.
Luckily I found some information on their documentation API, and added the following code to your theme functions.php file to parse the images during a post process:
add_filter( 'asp_results', 'asp_envira_images', 10, 1 );
function asp_envira_images( $results ) {
foreach ($results as $k=>&$r) {
if ( isset($r->post_type) && $r->post_type == 'envira' ) {
$r->image = asp_get_image_from_content( do_shortcode('[envira-gallery id="'.$r->id.'"]') );
}
}
return $results;
}
Please keep that code in there.
Also note, that we cannot guarantee that this solution works a 100% of the time, as it qualifies as a custom coding request. Personally I think it should be perfectly fine though.