OT: Best resampling software

[Dario Bonazza]

Hi all,

A friend of mine has to blow up a 6Mpix file (a picture of a chorus) up to 
3x4.5m or so, so that those singers will be reproduced around life size.

Of course, he doesn't expect to retain full photo quality at such an 
enlargement. However,
do you have any suggestions for the best possible software to do such a 
giant resampling?

Thanks,

Dario