Photos disappear and can't be re-inserted when editing an old post...

Hi - this has happened to me a few times now. 

I have noticed some errors (double posted pictures, typos etc) in a post, and when I go to edit it, the pictures all disappear. 

ok, I think. Delete them all and just re-insert them right? 

Nope. They don't appear then either. 

It's like editing a post makes you go through a one way "no pictures" portal into the upside down!

Any suggestions? 

The only work around I have found is to just write an entirely new post. That, of course, raises the other question (already answered on the forums) of deleting double or old / failed posts. Which you can't. So I am leaving an annoying trail of double posts for which I can only apologise. 

So... what say you forum gurus?