Quick test to see if using unlink is fast enough vs just symlinking directly.

linktest.pm

use strict;
use warnings;

use Benchmark::Stopwatch;
my $stopwatch = Benchmark::Stopwatch->new->start;
my $i = 0;

$stopwatch->lap("start");

opendir(my $dh, ".") || die "Can't open dir : $!";
while (readdir $dh) {
  next if /last|linktest/;
  $i++;
  unlink("last.png");
  symlink($_, "last.png");
  $stopwatch->lap("Link_$_");
}

print $stopwatch->summary(); #bogus, this can't handle time in ms