Unauthorised posts appearing

Hi, I’ve noticed 2 photos appearing on my social media (without any accompanying text) which I’m pretty sure I didn’t post myself. They don’t appear in my wordpress anywhere, but Buffer says they were sent using the WP 2 Buffer plugin. Is there a way to check how they got there? Any logs I can look at?

One photo was of a court jester holding up a sign saying “april fool”; the other was an advert for a Berlin radio station.

https://ww.wp.xz.cn/plugins/wp-to-buffer/