Microsoft's #TileArt app lets you customize your Windows Phone home screen
Called #TileArt, the app's been made by Ricc Webb, who works as "Mischief Maker" at Microsoft Mobile. It lets you create custom tile layouts using either your own images, or creations from the #TileArt Gallery that comes with the app. Transparent PNG files are supported, and you can easily share creations with friends.
The #TileArt app is free to download via Windows Store (see the first source link below). To celebrate its launch, Microsoft kicked off a contest asking creative people to make "original sets of art for the #TileArt app gallery." Open for the next 21 days, the contest will have 10 finalists who are going to receive a Lumia 930 smartphone each, and 4 grand prize winners who, in addition to a 930, will get a Surface Pro 3 tablet and $1,500. Official rules and details are available at the second source link below.
sources: Windows Store (download), #TileArt contest via Lumia Conversations