@c FIXME how is this priority determined?
loader will be used in practice depends on the priority of the loaders).
@c FIXME why are these uppercase when image-types is lower-case?
-@c FIXME what are the possibe options? Are these actually file extensions?
+@c FIXME what are the possible options? Are these actually file extensions?
For example, if you never want to use the ImageMagick loader to use
JPEG files, add @code{JPG} to this list.