Merging a PNG Cover Image into a PDF File

Overview

A memo for myself. This is because the text content and cover image of a novel distributed on BOOTH were provided separately.

How to do it efficiently

First, convert the cover (PNG image) into a single-page PDF using ImageMagick. After that, since it is just a matter of merging multiple PDFs, you can use qpdf to merge them.

# Make sure to install ImageMagick beforehand
$ convert cover.png cover.pdf

# Similarly, install qpdf
$ qpdf --empty --pages cover.pdf text.pdf -- combined.pdf

For now, this accomplishes the goal.

Conclusion

If you do not specify the cover size options, the sizes of the text and cover might be inconsistent.
I didn't know how to fix this with qpdf (or rather, is it even possible?).

I managed to fix it by printing the merged PDF to PDF again using Windows print functionality, so that's fine.

That's all.