How to extract the thumbnail and link to a different image?

Hi everyone,

It’s been a while since I posted last and I hope someone can help me with this. I recently returned to the tanzaku wp theme after having played around with it long ago. Just like on the Triple Ships website I would like to click on a thumbnail and be taken to the post where there are different images than the thumbnail on the main page (see the top middle post as an example: Title 1).

In the Index.php file I entered true for this value:
$flg_img_extract = true; // in single post page, extract thumbnail link to an original image.

But it doesn’t tell you how to do it when you are adding images to your post. I’m currently working on the theme on my localhost so I’m unable to give you a link as yet. Can anyone help me with this please?

Thank you.