so, you have a lot of jpg files and want to create one pdf out of it?
just that?
one the one side, there might be easier ways to do it (at least if you know how to write a script : - ).
scribus is not a bad tool for that (you can even automate the task by writing a script: not that i imply that you should do that) but, indeed, you might get a memory problem with all those big images.
from the screenshots, you seem to be on windows... and you could try to select all the jpg files in the file manager, in the context pick the "print" command and choose "to pdf" as the printer. i have no idea how good the result is... but it might be worth a try : - )
for linux i'm pretty sure that in 15 minutes i should be able to write a script for you that creates the pdf...
anyway:
- you have rather big images
- with some images you can load lot of images in one file, with other ones just 3...
- the same image works in one file but not in the other.
are the assertions above correct?
if yes, it would be good if you could give access to all your images (privately share a zip file with all the images and the .sla through framadrop or dropbox)... in the worst case you get a pdf with the job done... in the best case a solution for your issue...