I checked all the modules and they seem to be up-to-date (see below). I will say this, it seems to only happen if they post JUST a picture on the timeline (no words at all). Unfortunately, I cannot tell 'how' they are posting the picture.  (i.e. photo icon, link, etc.)

The following modules were successfully upgraded.

Channels module: up to 9.0.2 version.

Decorous module: up to 9.0.7 version.

Developer module: up to 9.0.9 version.

Froala module: up to 9.0.4 version.

Lucid module: up to 9.0.3 version.

Mass mailer module: up to 9.0.4 version.

OAuth2 Server module: up to 9.0.9 version.

Persons module: up to 9.0.11 version.

Polls module: up to 9.0.8 version.

Protean module: up to 9.0.11 version.

Timeline module: up to 9.0.13 version.