Hi there!

Thanks for your query.

You can use the following code in your custom CSS:

.speasyimagegallery-col-xs-2 {
    width: 50%;
}

Hope this will serve your purpose.

Note: Path towards custom CSS(Joomla 3): Extensions>Templates>Styles> Click on your current default template name then choose Template Options. Then find custom CSS within the custom code.

Best Regards

I have a supplementary question. How, on the contrary, with "Mosaic" I create smaller previews. It generates 3 columns and I would like 4 or 6? I modified the css to:

.speasyimagegallery-col-sm-4 {width: 24.33333333%;}

But it's not good. Is there a better solution? https://prnt.sc/iX2jgzduFBJu