At first I thought it would take too long to create a PDF from, let's say, 14 JPGs without a GUI. However, it takes surprisingly little time. I set Nemo and terminal next to each other, type "img2pdf" and then drag all the pictures, one by one, to the terminal. At the end I add "-o something.pdf", hit enter and in a moment PDF is created. Of course it would be nice to have a simple tool with GUI, but still img2pdf is very nice.
nice tools thank you