Hi Slobodan and Chris,
thanks for your concern.
The URL address line starts turning blue at left (selection color). After a while, a blank page appears with the address line filled in. That's it.
When I click re-load, it takes a while, then I get the message that I already submitted the post. "You might have accidentally double clicked, or tried refresh." So that was not what I was supposed to do... But the page was not posted, not even the text.
As you see, my images were jpegs, 4 x ca 500 kB, so the size was well within limits.
Good light - Hening.