Maybe think about storing the data in a single string and working it with vec. Vec can be sexy fast on certain tasks. OTOH, Perl isn't your friend when it comes to too much bit-twiddling. You likely should take the other's advice and look at Image::Magick or PDL. You'll be happier in the end if you can job image creation out to C routines.

--
$you = new YOU;
honk() if $you->love(perl)