Hi, I see the issue in some warnigs being generated, we have fixed this as well in next version. Buy do this inside inc/files.php search function: ppom_create_image_thumb
and replace with this:
function ppom_create_image_thumb( $file_path, $image_name, $thumb_size ) {
$thumb_size = intval($thumb_size);
$wp_image = wp_get_image_editor ( $file_path . $image_name );
$image_destination = $file_path . 'thumbs/' . $image_name;
if (! is_wp_error ( $wp_image )) {
$wp_image -> resize ( $thumb_size, $thumb_size, true );
$wp_image -> save ( $image_destination );
}
return $image_destination;
}