PHP help for get_the_category

Hi

I have problem with get_the_category. How to order categories?

I try to put this code above my thumbnails.

<?php
$category = get_the_category();
echo $category[0]->cat_name;
?>

My problem is with categories order. I want to show subcategory.

Here is example:

Thumbnail 1 Shows me the 2nd category of post
Thumbnail 2 Shows me the 1st category of post
Thumbnail 3 Shows me the 3rd category of post

I changed everything but is not working.