Mac dashboard widgets not loading external images

I set out to make a quick Mac OS X dashboard widget. I read the documentation and was pleased to find out they use simple HTML, JS, and CSS. I created my widget and it works when I open the .html file in Firefox, but it does not work when I install the widget 开发者_JS百科to the dashboard.

The widget is simple: it displays the most recent image from a weather web cam stream. The image URLs look like this: http://webcam.com/stream.jpg?1274213999617. The timestamp is appended to the URL and the server automatically responds with the latest image for that time. I did not write the server script.

The widget appears to be loading correctly, but the web cam image will not load. Notice the blue question mark in the upper left. The image should appear over the square background image. Is there any special procedure for loading external images into a widget?

alt text http://img.skitch.com/20100518-pfesqbaby8dcg6yet8wjay7n1c.jpg

You should look here for some important settings:

Dashboard Info.plist Keys