Every now and again I need to extract some images from a PDF. The best solution I have found is to use pdfimages on the command line in linux.

https://www.howtogeek.com/228796/how-to-extract-and-save-images-from-a-pdf-file-in-linux/

Get the tool in poppler set of tools as XPDF is out of date.
https://poppler.freedesktop.org/

Other helpful tools:

https://www.cyberciti.biz/faq/easily-extract-images-from-pdf-file/
https://askubuntu.com/questions/150100/extracting-embedded-images-from-a-pdf
https://superuser.com/questions/134869/how-to-extract-image-from-pdf-file
https://commons.wikimedia.org/wiki/Commons:Extracting_images_from_PDF