Bug 190981 The image id of image in different pages are the same
The id of image generated by the same report item (such as chart) are the same, thought the image contents are in different pages.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/presentation/LocalizedContentVisitor.java
if ( "Chart".equals( tagName ) )
		{
			IHTMLImageHandler imageHandler = context.getImageHandler( );
			if ( imageHandler != null )
			{
				String imageId = content.getInstanceID( ).toString( );
				CachedImage cachedImage = imageHandler.getCachedImage( imageId,
						IImage.CUSTOM_IMAGE, context.getReportContext( ) );
				if ( cachedImage != null )
				{
					IImageContent imageObj = getReportContent( )
							.createImageContent( content );
					imageObj.setParent( content.getParent( ) );
					
					imageObj.setImageSource( IImageContent.IMAGE_FILE );
					imageObj.setURI( cachedImage.getURL( ) );
					imageObj.setMIMEType( cachedImage.getMIMEType( ) );
					imageObj.setImageMap( cachedImage.getImageMap( ) );
					imageObj.setAltText( content.getAltText( ) );
					imageObj.setAltTextKey( content.getAltTextKey( ) );
					processImage( imageObj );
					return imageObj;
				}
			}
		}
		
		IReportItemPresentation itemPresentation = ExtensionManager
				.getInstance( ).createPresentationItem( tagName );
		if ( itemPresentation != null )