Download all original images from your Pinterest.com profile. Creates an entry in the Greasemonkey menu, just go to one of your boards, scroll down to the last image and click the option in the menu.
< Feedback on Pinterest.com Backup Original Files
I tried it with Firefox 44 and it seemed to work for me. Can write the exact URL that you are trying to backup? Or does it not work for any profile? And could you check in the Error Console if the script created an error (Press CTRL, SHIFT and J at the same time to open error console in Firefox).
Now all be good! Big thank you for your help! ^.^
firefox 44.0.1
Don't working on firefox 44.0.1 and greasemonkey 3.6