Jeff, the picture issues comes up from time to time and somewhat randomly. Usually it can be traced to "something" in one of the pictures you are trying to post and if you are posting multiple pictures, that one can hang up the whole post. What has worked for me is to type your text and then begin adding the pictures one at a time and trying to post. Once posted you can edit the post and add additional pictures (again one at a time). When it snags, you will know that the most recent picture is the cause. Usually re-editing the picture and resaving it to your computer will clear up whatever is causing the software to reject that particular picture. Its a PITA but fortunately doesn't happen that often. The process really isn't as tedious as it sounds like once you try it. Hope that may help some.
Bill
