You have two issues.... first you can't filter one recordset with a value from another directly using the default Dreamweaver recordset. Second your recordset's are in the wrong order.
First you need to move the recordsets to appear in the correct order. Copy lines 39-65 and paste them below the other recordsets maybe at the bottom just above the <!doctype> tag.
Then you will have to store a temporary variable above it. Add something like:
$_GET['artist_id'] = $row_WADAartworks['artist_id'];
Then you can update the bottom recordset to filter it with the $_GET variable instead of the recordset value.