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
}
	private void clearPreview( )
	{
		previewCanvas.clear( );
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.dialogs.Dialog#okPressed()
	 */
	protected void okPressed( )
	{
		try
		{
			switch ( selectedType )
			{
				case FILE_TYPE :
					inputImage.setFile( uriEditor.getText( ).trim( ) );
					break;
				case URI_TYPE :
					inputImage.setURL( uriEditor.getText( ).trim( ) );
					break;
				case EMBEDDED_TYPE :
					inputImage.setImageName( embeddedImageList.getSelection( )[0] );
					break;
				case BLOB_TYPE :
					inputImage.setValueExpression( uriEditor.getText( ).trim( ) );
			}
			setResult( inputImage );
		}