Display all attached image of every post of custom post type and link to original post

You have two issues here.

• The use of $image->ID in this line

  wp_get_attachment_image($image->ID, 'video-thumb');
  

This will give you the following error:

NOTICE Error: [8] Undefined variable: image

In all honesty, I think that should actually be $post->ID

• get_permalink() returns the permalink to the current post, which in this case is the image. If you want to link back to the post parent, you can pass the post parent ID to get_permalink(). The post parent ID can be retrieved with $post->post_parent, so something like this will do

  get_permalink( $post->post_parent );