To be honest, I am not exactly sure. The portion of code involves some simple Image::Magick and would run, but would not write the final output image from the external subroutine. I spent most of the day trying to figure out why the image wasn't being created.

I ended up slowly rebuilding the subroutine with small portions, and running with each small addition until the point when the image wasn't being written again, and it turned out to be the if elsif else portion. In the end, I had a subroutine with exactly the same code, with everything except that section.

I use strict and warnings, nothing ever showed up, so I can only assume there was some sort of collision with Image::Magick but not sure what. I even tried changing both $severity and $background to different string names, at first thinking maybe one of them was colliding with something, but still, no image would be written.

With both the hash version I did, and the one suggested by frozenwithjoy, they both work fine in the external sub.

I am still curious as to why it did not work that way, but in the end I am happy that I was at least able to track down what part of the code was causing the problem, and find a solution.