Picture posting is enabled for all :)
Why not just do a "Quote" reply and edit that, stating underneath that you have edited it.Ihave just tried it out and it works. Do a "Quote" of your original post and then edit the text. It will be a second post and won't affect the original.
If you need a post editing/deleting after the time limit has expired you would have to send Dan a PM asking him to edit it on your behalf.