How I can disable the glow effect ?

Add this to your custom CSS panel:

.gallery .gallery-icon img:hover {
	-moz-box-shadow: none;
	-webkit-box-shadow: none;
	-o-box-shadow: none;
	box-shadow: none;
	}

Hi acub, thanks for the help, but your code doesn′t work, you can check it.
Greetings.

I don’t see any glow effect. Do you mean the zoom in when mouse is over?
May be this helps you:

.gallery-icon img:hover
{
transform: none;
}

Solved adding this code to my custom css:

.gallery-icon img:hover {
  -moz-transform: none;
  -webkit-transform: none;
  -o-transform: none;
  transform: none;
  -ms-transform: none;
  -moz-box-shadow: none;
  -webkit-box-shadow: none;
  -o-box-shadow: none;
  box-shadow: none;
  filter: none;
}

.gallery-item img {
  box-shadow: none;
  -moz-transition: none;
  -webkit-transition: none;
  -o-transition: none;
  transition: none;
}

Greetings and thanks.

You meant the zooming effect? That’s controlled by transition. I thought you meant the box-shadow. There is no glow in CSS. ??

Yeah, i wanted to say the zooming effect, it has been a translation error ??
And it seems they have not got away: (
Thank you.

Just replace .gallery-icon img with .gallery .gallery-icon img, for both normal and hover states, so you override the plugin stylesheet.