I've put together my first skybox and when I enable the skybox it only appears as a textureless blank blue sky instead of the sky textures I put in the zip. Each of the 6 faces are 2048x and in .png, and I cannot find anything wrong with the files. I would appreciate it if someone could go through the zip and check for something I may have made a mistake on, or if there is anything wrong with the pictures I'm using, as I cannot find any. The sky thumb image still shows up in the environment, which puzzles me because the rest of the sky textures don't appear at all, and even though the sky color is by default set to white, not blue.
The sky is supposed to show up as a nebula
Link to sky:
http://www.mediafire.com/view/y95kdwkhl947a9j/Sky_Nebula.zip