

After opening and fitting the sky image I then used the filter / Other / Offset tool, to create tiles and make the texture tiled.


I set the offset 256 by 256 this created tiles in the texture, I then used the clone stamp tool to erase the lines going horizontaly and vertically through the image, I kept using the offset at the same settings and continued erasing the lines until it looked like a full sky.


The texture is now a tilable texture.