The whole album is stored in a dropbox-folder, which I share with my designer (my daughter). She made a beautiful logo as a png-file, which is stored in this album in the res-folder.
Unfortunately, I do not know how to add a relative path to the logo-file. If I click on browse it returns always the absolute path:
Under Settings > Effects > Logotype (I'm guessing that's what you're referring to), the path to the image must be local to the PC. All local paths are absolute - this is a requirement of the operating system, and jAlbum can't change that. So, if the path isn't the same on another PC, it won't work.
I don't think there's any solution to this. When you're working on the project, you have to browse to the correct image on your PC. When your daughter is working on the project, she will have to browse to the correct image on her PC.
jAlbum projects aren't really designed to be collaborative efforts, handled on two or more different platforms.
Instead of storing the logo file within the project, store it in a publicly-accessible location, like https://jgromit.jalbum.net/qm24.png. Copy and paste the URL into the Image URL field. Don't try to type it in by hand - that causes jAlbum to freeze.