To extract images from a .webarchive file, use the Termial app and command textutil convert -html [folder path to the webarchive file].
Follow these steps to disable SIP: Boot to Recovery OS by restarting your machine and holding down the Command and R keys at startup. Launch Terminal from the Utilities menu. Type in the following command and hit Enter: csrutil disable Now you can reboot your machine and empty the Trash. Remember to enable SIP again following the exact same steps, just with a different command csrutil enabl Reboot your machine again and you are good to go on your merry way.