You can use loops to iterate over the browsers, though, and you can use variables to avoid fetching the hash values every time:

my @browsers = ('firefox', 'chrome', 'internet explorer');
for my $b1_idx (0 .. $#browsers - 1) {
    my $b1 = $screen{ $browsers[$b1_idx] };
    for my $b2_idx ($b1_idx + 1 .. $#browsers) {
        my $b2 = $screen{ $browsers[$b2_idx] };

        unless ($b1->compare($b2)) {
            my $diff_file = $b1->difference($b2);
            print "#The images are not the same; see $diff_file for de
+tails\n";
            qx{ $diff_file };
        }

    }
}
[download]

Update: missing +1 added.

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,
[download]