You’re welcome! FWIW, digging deeper is one solution, but probably not necessary. It depends on what you mean by “deeper”. You mainly would want to manage the container width so there is no room for text next to the images. I’m making a big assumption about how the page is structured. This may not apply at all, but it is a pretty typical situation. Even if not, the general process is the same, only what rules are applied to what element change.
Use your browser’s developer tool (CSS inspector or something like that) to determine the container element and its applicable CSS. Try various width properties until the page behaves as desired. You likely would want a width specification similar to how the image widths are specified so they all respond similarly at different view port widths.
You may need to also repeat the process for mobile devices because these often have specific CSS that is applied for only small screens. OTOH, small screens likely have everything in a single column and it’s not an issue.
Once you’ve determined the right width style, add it to the “Additional CSS” section of the theme’s customizer.