Here's another way of doing it:

#!perl

use 5.12.0;
use warnings;

my @full = qw{
    0001.tif 0002.tif 0003.tif 0004.tif 0005.tif
    0006.tif 0007.tif 0008.tif 0009.tif 0010.tif
    0011.tif 0012.tif 0013.tif 0014.tif 0015.tif
    0016.tif 0017.tif 0018.tif 0019.tif 0020.tif
};
my @partioned = ([],[],[],[]);

for (0 .. $#full) {
    state $i = 0;
    push @{$partioned[$i]}, $full[$_];
    $i = ++$i % 4;
} 

my @subA = @{$partioned[0]};
my @subB = @{$partioned[1]};
my @subC = @{$partioned[2]};
my @subD = @{$partioned[3]};

say qq{@subA};
say qq{@subB};
say qq{@subC};
say qq{@subD};
[download]

Which outputs:

$ tif_split.pl
0001.tif 0005.tif 0009.tif 0013.tif 0017.tif
0002.tif 0006.tif 0010.tif 0014.tif 0018.tif
0003.tif 0007.tif 0011.tif 0015.tif 0019.tif
0004.tif 0008.tif 0012.tif 0016.tif 0020.tif
[download]

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