Hi there!

Thanks for your query.

The template set the max width value for a good view of the layout in a larger screens. Here is the related CSS: https://prnt.sc/26o434k

So, you can use the following code in your custom CSS:

.view-article .article-details .newsberg-details-img-wrapper .article-full-image {
    max-width: 100%;
}

This will give you fulwidth image.

Best Regards

Genrally, you want to avoid making the image 100 percent.

Why?

On mobile, the image will be very wide and short making it unreadable to the average person.

Bascially, not mobile friendly.

Genrally, you want to avoid making the image 100 percent.

Why?

For a person, a comfortable width of viewing and reading an article is no more than 900px. You can verify that by observing your own comfort with different reading width.

It would be worth it to reduce the width of the text in your articles if you take care of users and the quality of your site.

Joomshaper Blog is good example width of article.

So what about responsive? If image is 100%, it will not be so bad if it is responsive. Right?

Max-width does not prohibit the image of being 100% width on smaller screen sizes than max-width value

Thanks Pavel for your explanation...