PerlMagick is an object-oriented Perl interface to ImageMagick. Use this forum to discuss, make suggestions about, or report bugs concerning PerlMagick.
Do the temp files have the 'magick' prefix? If so, PerlMagick is caching your images to temporary disk. When the image is destroyed the temp files are removed. Of course if the process is killed, PerlMagick may not have an opportunity to clean up the files.
They won't get removed if PerlMagick gets a signal that it cannot catch (e.g. SIGKILL) otherwise they should be removed when the image is destroyed. You might try upgrading to the latest ImageMagick release and see that makes a difference.