Bug 193886 NPE is thrown when preview external CSS style in ppt[1205]
engine/org.eclipse.birt.report.engine.emitter.ppt/src/org/eclipse/birt/report/engine/emitter/ppt/PPTRender.java
{
			
			JPEGTranscoder transcoder = new JPEGTranscoder( );
			
			transcoder.addTranscodingHint( JPEGTranscoder.KEY_QUALITY,
					new Float( .8 ) );
			TranscoderInput input = new TranscoderInput( imageURL.toString( ) );
			
			ByteArrayOutputStream ostream = new ByteArrayOutputStream( );
			TranscoderOutput output = new TranscoderOutput( ostream );
			try
			{
				transcoder.transcode( input, output );
			}
			catch ( TranscoderException e )
			{
			}
			
			ostream.flush( );
			
			pptOutput.write( base.encode( ostream.toByteArray( ) ) );
		}
		else
		{
			FileInputStream file = null;
			try
			{
				file = new FileInputStream( imageURI );
			}
			catch ( FileNotFoundException e )