What is happening with my images disappearing?

This is so frustrating! I have uploaded a jpeg which seems to embed beautifully and then for seemingly no reason at all, has disappeared the next time I load the page. In its place is a blank box wit...

Does my course need to be published before I can send an announcement?

I'd like to send an announcement to my students but am not yet ready to publish the course. Can I do that? Or should I publish the course, send the announcement, and then keep tweaking the course? Th...