change link to attachment?

Pardon?

Well i have embedded wordpress inside my site and found a way to display only image from posts.
Now when you click on that image it takes you to wordpress attachment page, i want it to take me to post from which that image is taken BUT on my page where i would embedded content from that post.

I dont want to do anything with wordpress theme.

I have used this function to display only image from post:
https://bavotasan.com/tutorials/retrieve-the-first-image-from-a-wordpress-post/