Hi saqwild,

I don't understand exactly what you want to do (an example of what you expect would be useful)

[extension by rvelices] RV Menutree provides a replacement for the standard menu with expand/collapse icons. Either you can find it perfect for your use or you can take it as a model to know how to change the category menu.

I understand that you are talking about the main block on the page, not the menu. I mean where you have 2 categories on each line with thumbnail + description for each category. Right?

If you want to modify this, the best thing to begin is to create a template-extension that would replace mainpage_categories.tpl. Look at your "template-extension" directory and the [Administration > Configuration > Templates], click on the big "?" question mark to learn more.

The problem is that when you are on a category, Piwigo doesn't send the subcategory list to the template :-/ I know VDigital recently made some developments with a template listing subcategories. I notify him about this topic.

CSS rule

[extension by Piwigo Team] LocalFiles Editor
Tab ⇒ CSS,
add the following code at the end of the local-layout.css of your choice (in yoga = only for yoga):

/* to get 3 columns */
.content ul.thumbnailCategories li {
width:31%;
}

Try this:

/* to get 3 columns */
.content ul.thumbnailCategories li {
width:31% !important;
}