Saving background image to individual text slide does not work, 2019.1 or 2020.1. even with custom override.
I don’t know for sure, but maybe the underlying problem here is the same as for the on Quelea Github registered issue:
2020.0 CI release : user option ‘Allow custom item themes to override global theme’ broken #226
The programmers will need to dive into this.
Regards and blessings,