On ImageShack you can very easily host your images for use on your website/blog.

You upload your image via a form, via the rightmouse click in your webbrowser on any webpage containing pictures or via a rightmouse click in Windows and in return you get the "string" which you can paste on your website (or forum) to show the picture.

When you register you can even track the pictures you uploaded.

As far as i can "see" most of the world population is using imageshack currently for hosting pictures, its like a virus.