I need a gallery fixed

Site page that requires editing: https://unizchuey.com/index.php/art/

Within this page there are 4 'sections'. The 'gallery' is what needs coding. https://unizchuey.com/index.php/tattoo/#gallery

This is how the client wants it to display. It needs to work as a gallery allowing the user to click and open an image to view it. A black border around the honeycomb is important.

Currently the gallery does not not function properly and the images do not 'cover' the honeycomb layout. The code I used is from here: https://codepen.io/Rafiozoo/pen/NyMZRy

Please refer to https://unizchuey.com/index.php/tattoo/#gallery as it should look similar/the same style as this.

Thank you!