I do have a photo Gallery on my site, on laptop it works perfectly,
but on mobile view, the pictures 1st display well, and after a scroll, becomes very big & blur.

you can see on :

[hidden link]

A working demo can be find also on :
https://fivestar.mikado-themes.com/

I’ve search for hours but I can not get rid of this bug.
Any help will be much appreciate :*

EDIT : If i activate the original child theme, it works well. So it comes from my custom dev, need to find the one that create this troubles.

EDIT2 : After more investigation, the issue comes from
http://mv.gr3g.ca/wp-content/themes/fivestar-child/style.css

If i set back to empty style.css the issue disapear. Please fill free to inform me if you see anything wrong in it.