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Or, should/could we use (any) tool to make a bunch of 1-page PDFs, then some other (command-line?) tool to “combine all these 1-page PDFs into one PDF”, which might be a fast and cheap operation?
pdftk
https://www.pdflabs.com/tools/pdftk-server/
(hmm, can’t add image to pdf i don’t think, although can merge and edit metadata on pdf)
Uncaching on-demand derivatives
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