Look I don’t know what you and Free_Ality’s bias against rendering realistic clouds with BI is but leave flaming out of the topic.
Get a digital camera and take photos of clouds or textures or do this in a paint program oe 3rd party app. instead is two things I hear that try to block the advancement of Blender texturing and rendering features and tests. If everyone had the attitude, we can fake this or do this in a third party app. from the start we wouldn’t have SSS, raytracing, procedural textures, a compositor, and a whole list of other features, heck, would Blender even have a native renderer?