Pages always look better with illustrations. To use a picture on a page, first make sure that it is in the public domain or that you have the owners permission to use it if it is not your own. If it is your own, you are putting it in the public domain by publishing it on Folkipedia.
A picture can be a simple link to the image somewhere on the web e.g. http://www.folkipedia.org/images/neapolitan_mandolin.jpg but this method suffers from "link rot" - the phenomenon where sites disappear or get reorganised and links suddenly don't work any more.
Better than linking is to upload the images to a store at Folkipedia so they are always available, but only if they are yours or you have permission to.
Use the browse button at the top of page to browse for an image and click Upload to upload it to use on your page. When it is saved, it will be in the images folder, so your image link will be e.g. images/neapolitan_mandolin.jpg.