It's cool that your program works now. Presumably, since the solution was to put $infile inside single quotes, your SQL is inside double quotes not shown in your OP, as in

$sql = "UPDATE artists SET page=LOAD_FILE('$infile') where code='$code
+';";
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And if you are working with a list of values to be inserted, as you say, using placeholders will make your process much more efficient since the query can be prepared just once outside the loop. Assuming you had a hash of files keyed by code:

my $sth = $dbh->prepare('UPDATE artists SET page=LOAD_FILE(?) WHERE co
+de=?');

for my $code ( keys %hash ) {
    $sth->execute( $hash{$code}, $code );
}
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Hope this helps!

Yes, doing the prepare once will increase performance quite a bit.
Another thing that can make a HUGE difference in performance is running all of the updates (or insertions) as a single transaction. From one of my DB creation programs (million records). I like to make the "work" as a sub framed by BEGIN and COMMIT to make the transaction scope clear:

$dbh->do("BEGIN");  #a single transaction makes this MUCH faster
import_data();
$dbh->do("COMMIT");
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