(Found via CreativeBits)
Instead of hotlinking images and stealing the original host's bandwidth, you can use imgred.com to cache the image (you can even have it make a thumbnail) and use that link instead. While, for a blog post you would probably take the extra steps to download the file to your own server (providing this doesn't break any copyrights), this definitely makes sense for when you're posting on forums, etc.
To use imgred.com – just take the url of the image you want to link to and put "http://imgred.com/" before the URL. So instead of:<img src="http://myFriendsServer.com/theirImage.gif">
Do this:<img src="http://imgred.com/http://myFriendsServer.com/theirImage.gif">
To create a thumbnail – just put "http://imgred.com/tn/" before the URL – like this:<img src="http://imgred.com/tn/http://myFriendsServer.com/theirImage.gif">
(although when I tested the thumbnail functionality just now – it seemed to be broken… I'm assuming that will be fixed soon)