Imageshack is a great free image host and you may still use them, however effective immediately you may not link to an Imageshack page. They have entirely too many pop-ups and some of the ads are not appropriate for a family friendly forum.
So here's what you do....
From the image page on Imageshack copy the code to your clipbaord that says Direct
as shown by the red arrow in the screenshot below....
Now go to your post and click on the
icon above the post box. Now paste the code in between the [im
Voila, the image should now appear in your post when previewed or submitted.