This graphic was done in Photo Impact, utilizing the masking tool and various brushes & transparencies.  It was done very quickly and could easily have been "tweaked" to enhance it, i.e., more detail, applying a texture or a frame.

This was the original:

I can't show you the original on the next picture, because it was a full nude with tattoos everywhere -- just trust me on this.  I call this "Sisters".

This was using the Elliptical Gradient Fill of yellow to orange:

This was using the Rectangular Gradient Fill Pink to Blue:

Thanks to CC, this was using the Paint on Edge effect, using black & paintbrush:

...and with a sandstone texture applied, set at 1: