EZ Board has a system they call "EZ Codes". One of them is the [img] tag, which lets you post an image.

To add an image to your post, type [img], then copy or type out the URL of the image, then type [/img] at the end.

To get the URL of any image you have uploaded to our servers, go to your "My Images" page and copy the link listed as "direct address", without the "http://" part.

When you're done, you should have a line like this in your post:
[img]www.mysite.com/images/myimage.gif[/img]

Please remember that linking to images on servers/sites that you don't own is extremely rude and costs the person who runs the site money every time the image is viewed - please only do so after obtaining permission from the site's owner.