Hi Kena

You'll need to re-enter the URL of the image, make sure it contains the FULL image path starting with http:// and ends with the image filetype [.gif, .fpg, etc.].
To edit the post click the little pencil at the bottom right, then edit the image either by deleting it and reposting it or by clicking on the image and then clicking the image icon to re-enter the URL.
Feel free to post back if you need more help!