Go to your settings page and paste the following in the "Profile Picture URL" field:

https://steemitimages.com/DQmQCEA7eXwV9ZBrwWddHJKvVieMCKQk7i3kxoTxF9iFTEb/image.png

 
Then just hit "Update." Done!

For the record, I grabbed that URL from this very post! So, as long as the server hosting Steemit's images stays up, so will your profile picture!