My experience:
A pureref file may consist of embedded images and externally referenced images. This is great,
. . . but when you NEED to embed all images into the pureref file because linked images need to be moved or deleted, or the pureref file in question needs to be uploaded somewhere, I don't see a way to manually embed all images to ensure the pureref is safe to send out.
In order to manually embed all images the way I do it is to copy and paste all images from my existing pureref file into a fresh new one, while this toggle is turned on:
https://i.imgur.com/KyVHPRR.png
With this toggle on, saving your pureref file that contains linked images doesn't cause them to be embedded. It only seems to make a difference at the time of adding images.
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Suggestion:
Add two new right-click options:
Images > EMBED ALL - all images can simply be embedded in one command.
Images > Selection > EMBED - only selected images get embedded.