Most people simply don't read the docs properly for $content_width. Hopefully I can clear this up easily.
$content_width is a GLOBAL variable that themes and plugins can use to control media. We dont set it in PageLines, we leave it up to the user.
James was almost there with his example:
Here he is setting a var, but it isn't globalised so nothing can use it.
So lets assume for an example you have a page width of 1200px with a 800px content area and 200px sidebar... and you want the gallery to fit nicely in the content area..
OK what about if you have a full width page?
Get the idea?
Better yet, how can we make this use the settings from the layout editor? There are a bunch of functions added long ago in this file:
So on my full width test page here:To get the gallery to use the proper width i used this in my child theme functions: