It's pretty easy, I say that because I was able to do so after only 1 false start.
Register for a photobucket account, upload the pictures to that account, then with a browser open to the photobucket puctures, and a browser open here, post your text. When you get to where you want to put a picture, hit the tree looking button in the horizontal box between "Message" and the text box you type in. It's the fourth button from the right.
This will pop up a box, with a text box labeled "Image URL" and there is already "http" in the text box. I delete what's in the box, then I copy the URL from photobucket labeled "direct link" and paste it into the "Image URL text box, then click on the "Insert" button at the bottom of the pop up box.
This will put the bracketed text address of your picture in your message, but when you post it, it will show up as a picture. Mine are small pictures, but when you click on the picture in the thread, it gets bigger.
Hope this helps, now lets see some pictures!
Bill