List of ImageMagick types to treat as images.
Each list element should be a string or symbol, representing one
of the image types returned by `imagemagick-types'. If the
element is a string, it is handled as a regexp that enables all
matching types.
The value of `imagemagick-enabled-types' may also be t, meaning
to enable all types that ImageMagick supports.
The variable `imagemagick-types-inhibit' overrides this variable.
If you change this without using customize, you must call
`imagemagick-register-types' afterwards.
If Emacs is compiled without ImageMagick support, this variable
has no effect.