If someone can lift images from some of the linked to PDF files and post those it would help. Of course you'd have to check the copyright status.
British government publications have what amounts to a permanent Crown Copyright, but its seldom enforceable in the case of military manuals, in other publications a book may no longer be copyright protected but the images remain the intelectual propery of the photographer or artist.
Information itself can not be copyright protected, only the individual's literary or artistic contribution.
For copyright protected literature limited quotations are allowable for instructive purposes.
The US limits long term copyright protection, with anything printed before 1910 fair game and most books printed in the WW1 era are also fair game, though not all.
In some instances a scan of a book printed before WW1 can be public domain, but a scan of a recent reprint of the same book is protected and can't be posted.
Some books that are public domain in the US are still under copyright in the UK.