Install GIMP 2.8.4 in Ubuntu 12.04 and 12.10
For older versions of ubuntu there is no version 2.8. You could use the unstable version of 2.7 in ubuntu 11.04 and 11.10:
GIMP 2.7.4 is the last development download ahead of the stable GIMP 2.8 release.
Source packages for GIMP 2.7.4 can be found @ gimp.org/downloads/
To install GIMP 2.7.4 in Ubuntu via a PPA you will need to run the following two commands in a Terminal: -
This PPA contains unstable software
The PPA provides GIMP 2.74 builds for Ubuntu 11.04 and 11.10 only.