Images larger than text

Dear all
I have been reading about this but don’t seem to find any working solution.

I have this website with customized theme
https://www.barbaricinterior.com/

I simply want to have images larger than the text. To be precise, while I want my text block to be 600px wide, I would like my images to be able to be 950px wide max.

For you to know:
– I asked my web developer who worked on the theme, he tells me there is no way to do this in WordPress. I trust him but seems hard to believe.
– I worked with the media settings setting the max image width to 1024px, but even if I use it when adding media to the posts, it doesn’t work and images keep being automatically resized.
– If here in the style.css

img.size-full {
	max-width: 100%;
	width: auto; /* Prevent stretching of full-size images with height and width attributes in IE8 */
}

I change from max-width: 100%; to max-width: 950px; it works, but the images float in the page in a very messy way.

Is there any way around this using proper code in the css?

Thanks a lot for any help you might give!