$line =~ s/^\$mypic\[0] = "(\w{3})"$/$1/g;

##</code><code>##

my $newval;
if ($line =~ /^\$mypic\[0] = "(\w{3})"$/) {
   $newval = $1;
}
else {
   # handle failure to get essential value
}

##</code><code>##

my $newval;
unless ( ($newval) = $line =~ /(\w{3})"$/ ) {
   # handle failure to get essential value
}