Mailbag: How are images displayed for custom tiles on the Media Center Start menu?

Question:

I have read through the collection of posts that you wrote that describe how to customize the Windows Media Center Start menu in Windows Vista, and now I'm trying to create my own application and add it to the Start menu.  What are the guidelines for the icon that is shown in the custom tile on the Start menu, and do you have any best practices that I should follow?

Answer:

Custom tiles on the Windows Media Center Start menu in Windows Vista display an image that is 75 pixels by 75 pixels square.  If you provide a non-square image when registering your application, Windows Media Center will automatically scale it down and force it into a 75x75 square.

The same image is used for the Start menu tile as is used in the Program Library.

In order to allow your tile image to display as nicely as possible, we suggest using the PNG file format, and to size your image to be exactly 75x75 pixels to avoid having Windows Media Center resize it at all.

You can optionally provide an inactiveImageURL in addition to an imageURL when registering an entry point to appear on the Windows Media Center Start menu.  The inactiveImageURL will be displayed as the image for a custom tile when it is not currently in focus in the Windows Media Center UI.  If no inactiveImageURL value is provided, Windows Media Center will use a grayscale version of the imageURL when the custom tile does not have focus.

Windows Media Center automatically displays a "glowing" effect behind the 75x75 square image on custom tiles in the Start menu.  This glowing effect is bright on the left side of the tile and fades off towards the right.  When the 75x75 square image is drawn over the top of this glowing effect, it can cause the glowing effect to appear to be drawn incorrectly, especially when compared to the glowing effect that is displayed for built-in Windows Media Center tiles (which display uniform brightness and do not fade off towards the right.