Displaying inline images

I'm trying to display an inline image from a file via this script: https://iterm2.com/utilities/imgcat. It looks like it's doing something, because it displays the following:

Inline Images | block | allow this session | always allow

This should be some kind of dialog box, but it's only text. IIRC is ish based on the same emulator and there I get the dialog box and can click on allow, after that it's working the next time.

Displaying the image uses this esc-sequence: `printf "\033]1337;File=inline=%s" "$2"`