MAC上，安装imagemagic：
下载：
http://www.imagemagick.org/script/binary-releases.php#macosx
安装：
Create (or choose) a directory to install the package into and change to that directory, for example:
$ cd $HOME
Next, extract the contents of the package. For example:
$ tar xvzf ImageMagick-x86_64-apple-darwin13.2.0.tar.gz
Set the MAGICK_HOME environment variable to the path where you extracted the ImageMagick files. For example:
$ export MAGICK_HOME="$HOME/ImageMagick-6.8.9"
If the bin subdirectory of the extracted package is not already in your executable search path, add it to your PATH environment variable. For example:
$ export PATH="$MAGICK_HOME/bin:$PATH"
Set the DYLD_LIBRARY_PATH environment variable:
$ export DYLD_LIBRARY_PATH="$MAGICK_HOME/lib/"
Finally, to verify ImageMagick is working properly, type the following on the command line:
$ convert logo: logo.gif$ identify logo.gif$ display logo.gif
将PDF文件转成图像
#convert -density 150 -quality 100 -resize 800x "file.pdf" "result.jpg"
将file.pdf文件输出为result.jpg文件，如果PDF有多页，图像将自动以result-0.jpg' , 'result-1.jpg'...形式输出。
MAC上，用imagemagick把jpg转成黑白TIFF图的命令：
localhost:~ test$ convert 005.jpg -type bilevel -monochrome -compress group4 005.tif
localhost:~ test$ convert 005.jpg -monochrome -compress group4 005.tif
localhost:~ test$ convert 005.jpg -compress group4 005.tif
参考：
http://www.imagemagick.org/script/command-line-options.php