If you would answer my questions it would help a lot. Without answers it's difficult, if not impossible to establish what happened.You must validate your XenForo license to see quoted content
The update did nothing with the group Photo area.
Could you please right click on one of the missing photos and check the image properties to see if they actually exist on your server in the location shown when you right click on them? And what is the location?
Also, what version did you upgrade from when the images disappeared?
This error is saying that the forum for the group your were trying to delete doesn't exist.You must validate your XenForo license to see quoted content
Did you manually delete the forum from the Admin->Forums->Nodes list before attempting to delete the group? (this was possible in older versions of the add-on so you could have done it a long time ago)