Add support for locating arm64 freeimage dylib

[ssgraham767]

Partially addresses issue #851. I am not sure where to find a good source for directly downloading an arm64 compatible version of freeimage to guide users to in the FAQ. I used homebrew to get libfreeimage.3.18.0.dylib, but I am not sure how to best download the dylib directly. Homebrew Source: https://sourceforge.net/projects/freeimage/