What's up with pictures?

[frater secessus]

It's a bug:  https://community.mybb.com/thread-210977.html

Apparent workaround here (auf Deutsche):  https://www.mybb.de/forum/thread-34656-p...#pid228351

A common approach is to /** comment */  out the old line and paste in the new, rather than replacing it.  That will make it easy to revert later on.