Posting a picture without hotlinking:
If you don't want to download & upload the picture, use the "upload from url" feature. Highly recommended.
- Find the picture somewhere on the internet
- Copy the url (differs for each browser. For firefox, right-click on the image and choose Copy Image Location)
- In the cellar, click Manage Attachments below the message panel.
- Paste the url in the area noted Upload a File from a URL.
- Upload.
No muss. No fuss.