naming of linux-image package

[Magnus Pedersen <bofhenator@gmail.com>]

On http://packages.debian.org/sid/linux-image-2.6.25-2-686 I can read 
the following:

Package: linux-image-2.6.25-2-686 (2.6.25-5)

The 2.6.25 I get, but what is the difference between the -2 and the -5. 
My guess is that the -x is the debian build version, but why the 
different numbers?

/Magnus
Apologies, English is not my first language.