How do I actually accomplish this?

You have to use HTML - the img tag in particular.

<img src="filename goes here">

Optionally you can specify a width and/or height, which will scale the image accordingly:

<img src="filename goes here" width="100" height="100">

for a 100x100 (in pixels) display of whatever image you specify..

You have to find the hosting though, you can't "attach" an image to a post and have this website store it (unless you have GDNet+).

hth
Jack