With Joomla! You can create anything from a simple personal website to a complex ecommerce or social site with millions of visitors.
This section of the sample data provides you with a brief introduction to Joomla! concepts and reference material to help you understand how Joomla! works.
When you no longer need the sample data, you can can simply unpublish the sample data category found within each extension in the site administrator or you may completely delete each item and all of the categories.
These are my photos from parks I have visited (I didn't take them, they are all from Wikimedia Commons).
This shows you how to make a simple image gallery using articles in com_content.
In each article put a thumbnail image before a "readmore" and the full size image after it. Set the article to Show Intro Text: Hide.