Is it possible to use a local file for the redirect page?

[simon-friedberger]

I tried and it isn't working but maybe I have the path formatting wrong. I copied it from the address bar.
In case it's not clear, I have a local image on my disk that I would like to display instead of blocked pages.
I am on OSX and the path I tried looks like this: file:///Users/simon/foo_23234-2048x1367.jpg

[proginosko]

Firefox's security model doesn't allow extensions to open local files (unless they're packed within the extension itself). So you'll have to put the image on a web server instead and use HTTP access. I believe some users have made it work with a cloud drive like Dropbox or OneDrive.