Featured image link to attachment

Hi,
The featured image of the post, when clicked does nothing. 🙁 what i want is go to attachment page when Clicked.

That i want only on the post page and NOT on the Homepage –
Homepage is fine.

I have issue only with the “featured image” on the post page.

Thank you! 😀

HEEEEEEEEEEEEEELLLLLLLLLPPP! O_O