I am know the funktions in Qimage, and i am sugesting it to be the best to do the job, that means to maximise the use off the foto papers, to fit nice in the frame, and still have the overall porporsions off the poster picture when hanging on the wall, if Qimage could have a user interface a bit like PosteRazor, it would just be amasing...
please have a look at it here, if you would like to test my wish for qimage..
https://posterazor.sourceforge.io/

I found a wish to be able to make poster prints over multi pages, i found a software who have a layout i like, but exported in to PDF file, i did not like this, but it could cut out a border between the fotos to simulate the foto frame, in the way when many foto pages in frame hang on the wall the picture look right.
this would be nice to be able to do like this inside Qimage...

https://posterazor.sourceforge.io/index.php?page=download&lang=english