There are a few things that could be causing this.
First, make sure the path you chose can be gotten to while trying to post. Make sure the image bytes and not larger than the FAQs state (100Kb I think)
Also in the pic selection, go to the right of the Attach and change from "end-of-post" to "inline" the little drop down.
Then try to do a preview, this will NOT show the pic, but will show "attach=1" if all is well, then click on post.
IF you're still having problems you can even do the report the Admin and one of us can help more, either by responses or have you email the pic and we can look into why it might not post.
Bruce S