Pics can be confusing at first. There is a tutorial
http://www.mikenchell.com/pichelp.html
Basically, go to your album and click on one of the pictures. It will then display in a browser window.
Copy the url in the navigation window.
Now, in your post, when you get to where you want that picture to display, click on the IMG button above the text box, paste the url you copied, click on the IMG button again.
Then proceed with the rest of your life.