erro -> FPDF error: Some data has already been output, can't send PDF file
<?php require_once("fpdf/fpdf.php"); define('FPDF_FONTPATH','fpdf/font/'); $pdf= new FPDF("L","cm","A4"); $pdf->Open(); $pdf->AddPage(); $pdf->SetFont('arial','',10); $pdf->Image("img/certificado.jpg"); $pdf->Output("certificado.pdf","D"); ?>