In layman terms, hotlinking is using pictures/photos with the host's links/url on your own website etc. This will result in extended bandwith, causing the pictures/photos to disappear. And so, the pictures/photos have to be reuploaded again. Haha at least that's my understanding of hotlinking.
So moral of story, always upload pictures/photos on your own account
Omona mianhe! I didn't know the about that. Here's the direct link from dbsknights