imagemagick-render-type

imagemagick-render-type is a variable defined in `C source code'.
Its value is

0

Documentation:
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.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.1 of Emacs.