I have an image on Imgur and in the preview it just shows the link to the image and not the image itself.
Any ideas on what I am doing wrong?
You must be either Jr. Member rank, which requires 30 activity
(see this thread for more about activity), or
buy a copper membership. This is a limitation in place to help against spam, and you aren't doing anything wrong. If you want to post an ANN or something that is important and needs a image, ask someone to quote it for you so that it shows up (like I have done with the example), or wait ~42 days. Once you do reach a high enough rank, all of your images will automatically show up.