@Gotterdammerung @rolle That's sadly due to CORS, and I can't do anything about it. You would need to contact your instance admin and have them allow anonymous cross origin on the server that serves the media for your Mastodon instance.

A workaround could be to look up your profile on an another instance, and use that instance's link to the tool 🤷

Like this:
mementomori.social/@Gotterdamm