Since this comes up fairly regularly, I thought I should start a thread for it.
For those that do not know, we have a finite amount of image storage available here. More specifically, we are allowed 200 mb storage. When that is full, the software will not allow you to add an attachment to your post. The only way to free up space is to delete some of the stored images. Since I really don't want to loose anything that has been posted here, that means I will copy some, host them on my site, then edit the posts to remove the attachment then add the links to the hosted pictures. What that means for you, is that most of the time, it will take me a while to do that.
With that said, I just managed to free up 6 mb, so if you tried to post a pic, and it wouldn't let you, it should now.