Adjusting the banner image height on Squarespace

I've struggled to adjust the banner image height on several Squarepace sites. The projects have been spread out in time eough that I can't remember how to do it from one site to the next, so I end up digging through forums and stumbling my way along until I figure out the right way to do it.

So, today, I'm going to fix that. This answer from user Paul2009 I found on Squarespace's help forums seems to tbe the most simple and consise way to do it and I havne't found yet that it causes any bugs. Other methods I've tried, in contrast, did introduce bugs. So, I'm going to stick with this method from now on.

N.B.: For the more complicated situation of changing the banner image height for promoted gallery blocks in the Bedford theme, see this post.

Of course this may not work on all themes but it does work on Marquee and others I've tried.

To apply the change all of the banner images on the site, paste this CSS code in the Design > Custom CSS pane of the site editor menu.

.title-desc-wrapper.has-main-image {
    min-height: 100px;
}

To apply the change to only one page, place the code in the modified form below in the Header Code Injection tab of the Page or Post settings pane.

<style>
    .title-desc-wrapper.has-main-image {
    min-height: 100px; }
</style

N.B.: If you're not familiar with using custom CSS on Squarespace, do be careful as you can, as previously mention, mess things up in unexpected ways with Custom CSS and code injection. That said, there's no better way to learn than to try things and troubleshoot them!

Finally, if you don't want to mess with Custom CSS at all, the Five template includes a Banner Area Spacing tweak in the native style editor.
Source: Paul2009 on Squarespace Answers