It seems the problem I have is that imagemagick is being executed from /usr/bin in which an old version of imagemagick is installed on my server, I do not know how to make php exec() look in the right direction which is /usr/local/bin – that is the actual location of convert,
if I try using the full path with exec /usr/local/bin/convert then it does not work, exits with 127
I am on php 5.3.3 on cent os 6.3
Have you tried doing this?