Retrieve and display Database information without reloading page

I have a database full of image URLs that I need to display when required (revision site)

I can pull and display images from the database, however I would the page to load the next image in the database without reloading the page?

I would also like 'next image', 'previous image' buttons.

I am using python cgi scripts, sqlite and HTML.

How would I do this? (In Python please)

So on button press, it would execute a python script, retrieve the image URL from the database and then display it without reloading the page

Thanks