Please do not hotlink images (whether in your topics/posts, avatars or signatures). "Hotlinking" is when you link directly to a site's image. For example "http://www.wwe.com/johncena.jpg". Using that image would be hotlinking. If you wish to use images on the site, please make sure to upload them to www.imageshack.us or www.tinypic.com before posting.
As mentioned in the last sentence of the explanation, you can upload them to a variety of sites. Such as:
There are many others around the internet. Please, if you have images to post (such as reference pictures for CAW makers), upload them to an image uploading site and then post. It'll only take a few seconds.