Can’t find this plugin! Image viewer

Hello, I have been going crazy trying to find this
plugin.

I want to be able to do what the following 2 sites do with their images when you click on the thumbnails:

https://thegrumpiest.com/?p=4912

https://www.hollywoodtuna.com/?p=2869

When you click on the thumbnails you are redirected to a
new FULL page with header, footer, and sidebar with the photo enlarged. Also you may notice that the Title on the page’s title bar is determined by the link.

YOu can then click back to main page or the previous page.

Please help!

Thanks!