I add this line to my chapter in order to have an image.  Then I press "Save as draft" to see how it looks. After I "Save as draft" There is no picture and the picture command line is gone. What am I doing wrong?
You need to put this: https://i.imgur.com/eYDwyHF.jpeg between the ![]() I had the same problem, every picture ineed to be opened in his own tab. Than copie address from the tab
