Bug 183900 Image in preview pane will not show until you reopen the "Edit Image Item" dialogue [0001]
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/ImageBuilder.java
importButton.addSelectionListener( new SelectionAdapter( ) {
				public void widgetSelected( SelectionEvent event )
				{
					FileDialog fileChooser = new FileDialog( getShell( ),
							SWT.OPEN );
					fileChooser.setText( Messages.getString( "ImageBuilder.Chooser.Title" ) ); 
					fileChooser.setFilterExtensions( IMAGE_FILEFILTERS );
					try
					{
						String fullPath = fileChooser.open( );
						if ( fullPath != null )
						{
							String fileName = fileChooser.getFileName( );
							if ( fileName != null )
							{
								if ( embeddedImageList.indexOf( fileName ) != -1 )
								{
									ExceptionHandler.openMessageBox( DLG_TITLE_IMPORT_FAIL,
											DLG_ERROR_MSG_FILE_EXISTS,
											SWT.ICON_WARNING );
									return;
								}
								if ( checkExtensions( fileName ) == false )
								{
									ExceptionHandler.openErrorMessageBox( Messages.getString( "EmbeddedImagesNodeProvider.FileNameError.Title" ), 
											Messages.getString( "EmbeddedImagesNodeProvider.FileNameError.Message" ) ); 
									return;
								}
								previewCanvas.loadImage( ImageManager.getInstance( )
										.loadImage( fullPath ) );