I was looking for something similar, and just found a solution. Like the previous comments say, the project is opensource!
A quick and easy way would be to replace/download the image files in your server directory, and replace it with the photo name currently being used in kobo.
You have 2 directories to modify.
/home/kobo/kobo-docker/.vols/static/kpi/compiled
and
/home/kobo/kobo-docker/.vols/static/kpi/img
you can change these 3 files photo files,
signup_photo.jpg
kobologoS.svg — notice it is an .svg file and this is for the mobile version after you login the page
kobologo.svg – main logo in the loginpage and registration page
wallpaper takes effect in the first directory. Remember to use root privileges.
you can directly download and replace the name using the following command in your server terminal, download photo from a direct weblink
curl -o kobologo.svg weblink/picture.svg
a quick way to check if your photo is downloaded you can check it in your browser, for example:
kf.yourdomain/static/compiled/filename.jpg
and
kf.yourdomain/static/img/filename.svg
Hope it helps, let me know!
Omer
