First you go to "post an entry", and you click on the little image icon on top, like so:





Then you're gonna have to use a website that hosts images. I suggest http://imgbb.com/
Once your image is up there all you have to do is copy/paste the URL, and your image should appear in the post
If this doesn't work, I can make the post for you (just send me the text and image in a private message and I'll create it :D)