for(my $i=0;$i<4;$i++) {
  
     my $file = $q->param('pic_'.$i);
     my @full = split(/(\\)|(\/)/,$file);
     my $filename = pop(@full);
        $filename =~ s/\n//;
        $filename =~ s/\r//;
        $filename = $username_pic."_".$filename;
        #$filename=~s/^([^_]+_)(.*)(\.\w{3})\z/$1.md5_hex($2).$3/eg;
        my $md5 = md5_hex( $filename );
        $filename =s[_(\d+).jpg$][_$md5.jpg];
}