sudo apt-get install imagemagick

Some packages could not be installed. This may mean that you have requestedan impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming.
The following packages have unmet dependencies:
imagemagick : Depends: imagemagick-6.q16 (= 8:6.8.9.9-7ubuntu5)
E: Unable to correct problems, you have held broken packages.