User blog comment:Zikimura/Ohayo Ziki-sensei/@comment-24259262-20131223034113/@comment-4728047-20131223035347

like Djoletz told InRainbowLand below

you type:

File:PictureName.jpg|250px

and then put it between double brackedts =

of course you'll have to change the .jpg if the image is not a .jpg (see the File name in the New Images area)