Lines between images

[TrendBlend]

Hello, I got this code Oct 18 2:04 PM - Codeshare for displaying this:

But I want to add straight horizontal lines between the images, like I added in the image. But it is not working, can anyone please help me with this? Thanks in advance!

[Hey_Jak]

Use pseudo Element :before ; https://developer.mozilla.org/en-US/docs/Web/CSS/::before