"Hotlinking" also describes linking directly to on image on another server.
This can be good, as in forums. You are required to have the image somewhere else, so when it is loaded, it's traffic on your webspace, not on the forum's.
However, hotlinking an image on a server that does not belong to you can put a lot of traffic on that server. Basically, you are stealing bandwidth. normally, webmasters do not like that too much.
So when using images on your pages, make sure to download them, upload them to your webspace and link them from there.
::emp::