Here is a link to a pet package for Ufraw - RAW format image editor that also integrates well with GIMP.
The Slacko repos only have version 0.18 that will not handle the NRW image file format produced by the Nikon P7800.
This was compiled from source from the Debian Unstable branch in Slacko using the devx.sfs
Haven't tried it yet in other Puppies, but it is likely to work there as well. Let me know how it goes.
1.3MB - Get it here:
http://ubuntuone.com/3HZcAN8qra3iJiA9ozlz2q
edit: If you are having dependency problems with this, open the Slacko Package Manager and search for ufraw. This will come up with ufraw version 0.18. If you click on this package item, you will see a listing of required dependencies - including Gimp, lensfun and others. These are all to be found in the Slacko repos. Simply install them to get ufraw 0.19 to run.
ufraw for slacko 5.7
ufraw for slacko 5.7
Life is too short to spend it in front of a computer