als antwoord op
Don't forget that there are also dragons if you download and serve those images yourself, just different dragons that might get your own site hacked. See for example how I hacked my own site that was using a Webmention plugin by someone else: https://seblog.nl/2017/02/13/3/how-i-hacked-my-own-site
The IndieWeb loves context, but external content always comes with a risk.