Boxes & Question marks

Thanks for input.

It will be very difficult to trace all the images i ever used and place it in a folder and the presentation.
And the thing is: every iwork user must do that? It worked perfectly before.
I would take the file to another mac having iwork installed and it would function perfectly.
For many years.

Why it happens all of a sudden without having changed system or mac, a 2011 imac which is regularly
kept well with diskwarrior & onyx? Clean and proper in all respects?

Something has gone wrong and i should like to correct it. There must be somewhere a cause and a way out of it.

Thanks again.

Kind regards