jpgraph中出错" 图像因其本身有错无法显示"

<br /><?php <br />require_once ('jpgraph/jpgraph.php');<br />require_once ('jpgraph/jpgraph_bar.php');<br /><br />$datay1=array(13,8,19,7,17,6);<br />$datay2=array(4,5,2,7,5,25);<br /><br />// Create the graph.<br />$graph = new Graph(350,250);<br />$graph->SetScale('textlin');<br />$graph->SetMarginColor('silver');<br /><br />// Setup title<br />$graph->title->Set('支持布什的人数统计(万)');<br />$graph->title->SetFont(FF_SIMSUN,FS_BOLD,14);<br /><br />// Create the first bar<br />$bplot = new BarPlot($datay1);<br />$bplot->SetFillGradient('AntiqueWhite2','AntiqueWhite4:0.8',GRAD_VERT);<br />$bplot->SetColor('darkred');<br /><br />// Create the second bar<br />$bplot2 = new BarPlot($datay2);<br />$bplot2->SetFillGradient('olivedrab1','olivedrab4',GRAD_VERT);<br />$bplot2->SetColor('darkgreen');<br /><br />// And join them in an accumulated bar<br />$accbplot = new AccBarPlot(array($bplot,$bplot2));<br />$graph->Add($accbplot);<br /><br />ob_clean();<br />$graph->Stroke();<br /><br />?><br /><br />