Note: The content in this blog post references the Beta release of the Windows Phone 7 tools.

The Basics

A Windows Phone 7 application has two icons to represent it on the phone

• The application icon appears on the start screen when your application is displayed on the start screen (the complete list of apps on the phone)
• The live tile background appears on the home screen if a user thinks enough of your application to pin it there.

The application icon	The live tile background icon

Both of these icons are PNG images created by default when you create a new Windows Phone 7 project in Visual Studio.  ApplicationIcon.png is 62 x 62 pixels and Background.png is 173 x 173 pixels.

The most important thing to understand about the live tile background is that it is not your final live tile – it is the background for the live tile.  Windows Phone 7 will put other information on top of your icon, including the title of the application (as seen above) and tile notifications.  For these reasons, be sure to keep your image out of the way of the space reserved for these elements.  This MSDN page has more details.

Moving the icon files in your solution

If you don’t like the icons hanging out in the root of your Visual Studio solution you can move them without any trouble.  You can also rename them.  The names and locations aren’t important so long as you remember to update your project properties.

Here, you can see that I’ve created a copy of each of my icons and moved them both to a new folder.

Now in my Project Properties, I see all four icons and can select any that I like.  Also notice that I can change the Title of our application from this same Properties page.  It’s noteworthy that the app can have one name on the start screen and another name when pinned as a live tile.

Marketplace Icons

In addition to the application icons that will be displayed on the phone, you will need to submit two additional icons for the Windows Phone Marketplace.  The guidelines state that the Marketplace icon must “closely match” the icons used on the phone. 

The marketplace icon is used the represent your application when browsing either on the phone or on the desktop.  More details area available in the “Windows Phone Market Iconography” section of the Certification Requirements (Download the PDF)

Conclusion

Creating icons for the Windows Phone couldn’t be easier.  And the flat, 2D style of Windows Phone 7 makes it even easier for developers to create icons that match the style of the phone itself.

Additional Resources

• Application tiles: http://msdn.microsoft.com/en-us/library/ff462080(VS.92).aspx
• UI and Design Interaction Guide: http://go.microsoft.com/?linkid=9713252
• Certification Requirements: http://go.microsoft.com/?linkid=9730558