Variable: imagemagick-render-type

Integer indicating which ImageMagick rendering method to use.
The options are:
0 -- the default method (pixel pushing)
1 -- a newer method ("MagickExportImagePixels") that may perform
better (speed etc) in some cases, but has not been as thoroughly
tested with Emacs as the default method. This method requires
ImageMagick version 6.4.6 (approximately) or later.