Alignment Issue

Hi!
I’m using Simple PhotoSwipe and it is really cool and easy to use, but I have an issue.
I upload my images inside a gallery in a specific order, but once I go for the Simple PhotoSwipe it changes the order and aligns the images vertically rather than horizontally.
When I scroll the first image, the second is the one below the first and so on.
PhotoSwipe reorder the pics in column insead for row. I noticed in your demo as well.

Do you know how can I fix it?

Cheers,
Cristina

https://ww.wp.xz.cn/plugins/simple-photoswipe/