All you need to do to customize the looks is:  

Once you have installed Modern Tile Maker, run it and set your choices, check the Preview, and if it meets your preferences, click on Pin to Start. You will now be able to see the App-style tiles for your legacy applications, files and folders too. You can create Tiles with Modern UI for My Computer, built-in Windows tools and all other elements too.

  There are some ready-to-use Transparent Tile Icons that have been included along with the download. These number over 100 and come in 2 styles. Tiles you create will be stored in C:\Program Files\MTM\Tile Images\User Created Tiles The size of the Tiles are 150×150. Larger images will be scaled down to fit. The process of generating the Tile images is efficient and pretty good at keeping the image quality without any loss. We recommend using Transparent Images as it gives a better option of selecting colors for the Tile. The option for Wide Tiles is currently unavailable. Features in a nutshell:

Add any File type to the Start screen. Files such as Images launch using their default program.Add any Directory(Folder) to the Start screen.Add Web Shortcuts to the Start screen. Just enter the address of the webpage you want the shortcut to direct to.When you begin to create the Tile you will be prompted to select your default browser.   Choose the Text to display on the tile, Text Fore-color or choose to not display Text on the tile.Choose a Color for the tile which is shown if the image selected is transparent or not 150x150pxCreates a Backup the tiles settings to allow you to Edit the tile whenever you choose.Creates a Backup of the Tile Image you create for use with other tiles.Includes 100 Transparent Tile Images formatted for use when displaying text or not displaying text (200 total images).

NOTE: If you make any changes to your computer or something just goes wrong and all of a sudden your Tile Icons display a standard Desktop icon instead of the Modern (Metro) Tile, load the application and click the Refresh Button. Give the Start Screen about 30-60 seconds to refresh itself and see if the tiles refresh themselves back to the Modern (Metro) Tile. If no changes still, Restart your computer and see if it reverts the changes back. If all this fails you will have to unpin the tiles from the Start Screen, open the application and re-pin them using the backups that were created.

Download Modern Tile Maker. Once you have installed it, create a system restore point and then go ahead and create Metro Tiles for even your legacy software, folders and files on Windows 8. If you wish to uninstall Modern Tile Maker, you can do so via the Control Panel. If you have any questions, our developer Lee Whittington will be happy to help you out at the forums.