This is essentially the same Spikey Spiral Droste effect as this picture.  It was based upon a photo of tree branches taken in my back yard.  Some of the branches crossed each other to form a roughly diamond shaped area near the center, and that region was made transparent by using the GIMP graphics program.  The Wipe Tool was applied with various options to turn the original blue sky into more flamboyant colors.  Then the Droste Tool Spikey Spiral was rendered.  Of course, any Liquib Tools and Effects can be combined with Droste manipulations.  If a transparent region exists in the original source image, it will continue to be detected by the Droste Tool after other manipulations.