I realised it was going to be too large to work with when the software was about half way through the fourth of 16 images about five minutes later.
So I shut the program down, except it was too busy shuffling stuff around and didn't respond to me, so I had to use End Program.
End Program gave me a little dialog telling me my program had perfomed an illegal operation and would be shut down. Fine, I said, I wanted it it shut down IN THE FIRST PLACE.
So I waited til it had finished sorting its merry self out, and double-clicked the icon to get the program back again, so I could deal with the images in smaller chunks.
And so it came back to life, and lo! Behold the reloading of the "recovered document". Or rather 'attempted reloading', since the non-loading was the original reason for giving up.
:bu: - "As interesting as THAT" (tm)