geniusrmd

Solved it by changing code.

Commented out line 185:

// $image_size = wp_get_attachment_image_src( get_post_thumbnail_id($post->ID) );

And, this code block stating at line 233:

// if ( $image_size && has_post_thumbnail() ) {
//
// echo ‘‘ . get_the_post_thumbnail( get_the_ID(), $image_size ) . ‘ ‘;
// }

Errors were gone after that.