With inkscape one can open and edit PDF files. But when the PDF comes with embedded images, the resulting SVG keeps the images as an embedded base64 encoded data. I wanted to extract those embedded images from the resulting SVG. But I didn't want to use the "export bitmap" option on Inkscape to extract those images, as whiting this way I wouldn't really know the original resolution besides the fact that Inkscape would re-encode the image data. So I wrote this one line to extract all images from one SVG.
i=1; grep data:image test.svg | cut -d "," -f 2 | cut -d \" -f 1 |while read line ; do echo $line | base64 --decode > $i.png ; i=$((i+1)); done