The extension .jpg is necessary, and the case and spelling must match. Make sure the image has read permission for everyone. Make sure the URL is in quotes. If the image was ftp'd, make sure it was done in binary and not ascii mode. The format of the page looks very strange.
Some tags require a closing tag, so be sure there is matching closing tag.
Make sure all quotes have a closing quote. Be careful nesting the tags. Poor nesting can lead to unpredictable page formatting. You believe you have corrected the problem, but the browser still displays the page with the incorrect format. It is possible that the page the browser is displaying is in a different location from the one that you are editing.