in reply to Annotate and Image::Magick
I don't know much about the sh: gs: command not found. Probably the shell missing something.
I can offer a suggestion about aside, the print statement is being buffered in STDOUT by perl. I think if you put $|++; somewhere near the start of your script, you will disable outbuffering.
$| is documented in perlvar.
Michael,
the blue haired monk.
In Section
Seekers of Perl Wisdom