Δημοσίευση εικόνας στο χώρο συζητήσεων. Photo's publication on discussion forum

I see the advices to publish photo but I can't make it. https://www.duolingo.com/comment/2591660. I don't understand how to use imgur. Can you help me?

In other words: 

Advices for download photos in discussion forum:

Image Linking: becomes

(Remember to first upload your image to imgur and then copy the specific imgur link they give you and insert it properly. Don't forget the "!")