A free program for Android, by Thropical Tools.

Sky Filter is an easy-to-use, versatile photo editing app for iOS that gives you the tools to make any picture look like a sky. In just a few minutes, you can apply an overlay of any shape, color, and texture to your photos.

It offers a wide variety of overlays that you can choose from, including a sky, clouds, rain, snow, stars, and even an overlay of your favorite photo. You can also apply a different filter to your overlay, such as a blur, a vintage, a color, or a texture.

To make your photos even more impressive, you can add a variety of other effects, such as a lens flare, a rainbow, or a storm. You can even add a background that will change the color and brightness of your photos.