after update border around image – how to delete in wp

Hi there,

After update borders appear around images in the lightbox. How dan i delete these?
On other pages on my website, no borders appear around (single) images!

I read i can change the css:
img {
border: 0px!important;
}

But i don’t see where in the txt i can put this (plugin editor lightbox plus colorbox)??
Just editing doesn’t work…

The solution may be simple?

I hope you can help?
??

The page I need help with: [log in to see the link]