Hey Ciaran, I remember a few days ago you thanked me for adding an image to Grangers Hoggary, but you said that you didn't know how to add the picture yourself.
Assuming you're using the visual editor: Click on the infobox and a little black box should appear with the puzzle piece icon (meaning it's a template) and the title of the template type. From there, click on the name and you'll get a pop-up box that lets you edit the fields inside the infobox. Where you see the "image" field you can click on the red button to the right of it that has a little clip art of a photo on it. From there you can upload and title your new photo, click "Apply Changes," click "Apply Changes" on the infobox popup, then save your page. After all that, you should see your image on your page. You can also simply put photos in the body of an article or just upload them to the wiki itself for other users to see.