For some reason Omeka had problems with an install of ImageMagick using MacPorts onto a Mac with OSX Lion. It may be because it installed the distribution file into /opt/local. I could not get Omeka to work no matter what directory path was specified.
To get it to work I downloaded ImageMagick 6.7.1 from http://www.macupdate.com/app/mac/12447/imagemagick. Double clicked the tar file to decompress it. Then I manually dragged and dropped the distribution files into their proper folders at /usr/local/. After specifying the ImageMagick path as /usr/local/bin and clicking the TEST button on the Omeka General Setting page I got "Works" and adding a photo item also worked.

