Hight relosution post image

For thumbnails, I found wp_get_attachment_image_url does not return high resolution thumbnails. I replaced it with get_the_post_thumbnail.

I am wondering if we can make the get_the_post_thumbnail as default so I can update this plugin without having to modify it later?

Or is there a way to add a hook to replace the thumbnail anchor link?

I have 2 examples:

Before (blocks/Post_Grid_4.php at line 2086):
$post_loop .= '<a href="'.$titlelink.'"><img alt="'.$title.'" src="'.wp_get_attachment_image_url( $post_thumb_id, 'full' ).'" /></a>';

After:
$post_loop .= '<a href="'.$titlelink.'">'.get_the_post_thumbnail().'</a>';

We need to change it for each post type, for example: blocks/Post_List_3.php

vim ultimate-post/blocks/Post_List_3.php + 2289

before: $post_loop .= ‘‘;

after: $post_loop .= ‘‘.get_the_post_thumbnail().’‘;