Combine multiple image files into a single PDF file

Question

What's a good utility for combining different image files (e.g. PNGs or JPGs) into a single PDF file, with no quality loss (or minimal quality loss)?

Required features:

• Libre
• Gratis
• Command-line
• Runs on Linux
• Runs on x86_64 machines

Desired features:

• Cross platform
• Fast

Answer 1

One possibility is to use imagemagick on each image individually:

convert foo.png foo.pdf

then combine them all with

pdfunite foo.pdf bar.pdf baz.pdf output.pdf

but make sure to list the PDFs in order. pdfunite is part of the Poppler project, and is FOSS; and so is imagemagick.

Caveat: imagemagick re-compresses (and possibly even changes the resolution) during conversion, so this doesn't really wrap the images in a PDF.

Answer 2

A GUI utility for doing this is gscan2pdf. While it's oriented towards scanning images, it supports combining images in a PDF very easily:

1. Launch gscan2pdf.
2. On the menu, choose File | Open.
3. Choose your files.
4. On the menu, choose File | Save.
5. You can usually ignore the resulting dialog; press Save and choose a target filename.

That's it! Quick and easy and you don't have to memorize anything.

gscan2pdf supports several common formats including JPEG, PNG and TIFF - and also images already wrapped inside a PS or PDF file, but those need to be one-page PS or PDF files.