In my opinion no - using bicubic interpolation sevaral times in stead of just one does not give better results.
I tried with 9 different pictures (from a wide range of scenes), and none of them seemed to be better with the many-step enlargement. Only the text in an image looked a bit better, but in natural images some artefacts were introduced. There are also some mathematical resons why a single-step anlargement should be better than multi-step becuase each step will throw away some information.
But this is also something that is very different between different algorithms. With bicubic interpolation the multi-step approach is ok (but not good), but with bilinear interpolation the result is quite hopeless (too smoothed).
If you are comparing different image-enlargement algorithms I can also recommend trying the Wiener methods in Image Analyzer. They are superior to bicubic interpolation on most pictures. Actually they are related to the fractal method, but much faster and with less risk of producing strange artifacts (and then its free ).
But which algorithm performs best probably always depends on the individual picture and how much enlargement you want... Many programs exists for enlarging pictures in many different ways and I think the ones available in Image Analyzer are okay, but I wont claim they are the best.
> software developer <