Post anomaly with attachement details inserted

Hey

My problem is that when I write an description or in same cases caption into a picture I am adding, then the final result will show up extra small in private browsing of Firefox window.

Example when it is working:
http://www.andressoop.com/2015/06/19/fierce/
<img src="http://www.andressoop.com/wp-content/uploads/2016/02/2015-06-19-Liisiga-Viljandis-018.jpg" alt="Fierce" width="2000" height="1325" class="aligncenter size-full wp-image-3091" />

Example when it is not (also description is added):
http://www.andressoop.com/2016/02/01/a-frame/
[caption id="attachment_3094" align="aligncenter" width="2000"]<img src="http://www.andressoop.com/wp-content/uploads/2016/02/2016-02-01-Koduhoov-001.jpg" alt="A frame" width="2000" height="1325" class="size-full wp-image-3094" /> Nikon D5100 - f2.8 - 1/800 sec - ISO 640 - 135mm[/caption]

What I have noticed about this anomaly: When I click “Preview Changes” it shows up correctly. It also works on my tablet using Internet Explorer. It does not work on Firefox browser Private Window (works in regular view).