Problem with uploaded images

When I add an image URL to a forum, the image shows up for a few hours only. Then, it show another image with "Hot Link or Icon.com" instead of the uploaded image.

How can I solve this problem?

Thanks.

That is because you are hotlinking, which is illegal. Hotlinking is where you use another site's bandwidth. What you need to do is to go to that site where you hotlinked from and save the image to your computer. Then you just use a simple image host like imageshack, or tinypic and then use that new link that they give you.