Okular 1.0.3 in Kubuntu 17.04 Okular's stamp tool would be much more useful if you could choose a picture file from your computer to use as a stamp, instead of being limited to a static list of built-in images. The particular use case I'd like to enable is stamping a picture of my signature, for the purpose of signing digital documents.
https://docs.kde.org/trunk5/en/kdegraphics/okular/configannotations.html
Thanks Albert. I was able to use it successfully! It could be made a bit more discoverable, though. For that, I have filed https://bugs.kde.org/show_bug.cgi?id=383652