I had some questions regarding the gallery filter customization for the XI theme. The biggest issue is that I can get it to show the filter, but whenever I click on a category nothing comes up. You can see what I mean here:
You have to have posts in your categories, preferably with feature images.
Obviously on most sites not all categories with have images, and some categories (as on your site) are empty, so the best way is :
1. create a gallery category
2. create child categories under that category
3. put your posts in the child catgeories and make sure they have featured images
4. set the category_name on the gallery page to your parent category
Actually it seems to be a different issue, possibly a bug. The categories I have that are one word will show up with either pictures or text, but the categories where the category name is more than one word long will not show up. It seems that it’s trying to filter by the litteral category name instead of the category slug.
For instance, the category called “Web Tips” has a category slug of “web-tips”, but when you click on the filter, the URL query shows up like this: