What is the difference of tilesize and levelsizes ?????????

Hi all,

with krpanotools Config File Reference(multires.config):

1,tilesize:Size of the multi-resolution tile images.

2,levelsizes:Set manual level sizes by a comma-separated list.

but what is the difference of them?

E.G. tilesize set to " 512" and levelsizes "256"?

thx