Pictures Fail to Display in Events

This issue just started today. I have posted one event per day for months and, until today, never had any issues. Today, although pictures display completely normally in the edit window for my events, they are absent from the events on the event list. There is just blank space where the picture should be. I have tried multiple times with some, and the result is always the same---it looks normal in the edit window, but there is no picture on the event list.