Full Width / Responsive Gallery

Good day

I want to display 5 images in a row (portrait & landscape) that is the same height but it must stretch full width of the screen. I’ve noticed that it doesn’t fill the entire screen when I view the page on larger screens. How can I fix this?

https://www.dropbox.com/s/28johwudf4tvnb2/Screen%20Shot%202018-12-07%20at%204.05.16%20PM.png?dl=0

Thank you very much!