Grouping galleries with Colorbox modules
The content-type "gallery"

First of all, I created a content-type "gallery" which has several fields of my choice and a field "image" with illimited number of images.

The View

If I don't want something too specific, I use the Views module to create a View of all my galleries. I hope you already know that module. If not, go read the basics.


Choose content of type gallery
Set the title and the path of the page, etc...


You can choose which fields to show. If you want something like the site you linked in your question, you can use this configuration:


Format: grid (with number of columns to 4)
Fields:


Title
Image


Image style to thumbnail or whatever you created
Link to content (to land on gallery page when you click on the image)
Multiple value fields settings: display 1




Normally, you have now the equivalent of http://www.hopkinsco.com/portfolio when you open your View page.

The gallery page

The page of the content-type gallery displays all the fields you created for this content-type, in the order you arranged them in the admin. If you want something simple with the Colorbox module, you can go to admin/content-types/gallery/manage display and set the image field config like this (sorry for the french):



Then go click on the little gear on the right to set the advanced config:



Now you've got the equivalent of http://www.hopkinsco.com/portfolio/colonial.

The template and/or the style

Now that you've got the right content in the right place, you can customize the rendering with a little template and/or CSS.