I used terminal to install gimp and it says :
Some packages could not be installed. This may mean
you asked for the impossible, or if you use
the unstable distribution that some required packages have not yet
created or are not out of Incoming .
The following information should help you resolve the situation:
The following packages have unmet dependencies:
gimp : Depends: libgegl - 0.3-0 (> = 0.3.0 ) but will not be installed
E: Unable to correct problems , defective packets are " keep state " mode.