Command line to create a PDF document from a batch of images

How to create a PDF document from a batch of images ? === Belowis what I tried before posting this question: The **ImageMagick** way, but the PDF document generated is too big: convert *.ppm book.pdf The **Preview** tool way, the created document is much smaller but it creates margins. The **sips** way, not working for some reason: sips -s format pdf *.ppm --out 'book.pdf' 1>/dev/null 2>&1 There also **img2pdf** which looks good but I couldn't install it on mac (it's not in brew's list of packages).