Hi,
you have to set your own preview image URL when you create your predefined demo imports, like so (notice the import_preview_image_url array value, this needs to be a valid URL to your import preview):
function ocdi_import_files() {
return array(
array(
'import_file_name' => 'Demo Import 1',
'categories' => array( 'Category 1', 'Category 2' ),
'import_file_url' => 'http://www.your_domain.com/ocdi/demo-content.xml',
'import_widget_file_url' => 'http://www.your_domain.com/ocdi/widgets.json',
'import_customizer_file_url' => 'http://www.your_domain.com/ocdi/customizer.dat',
'import_preview_image_url' => 'http://www.your_domain.com/ocdi/preview_import_image1.jpg',
'import_notice' => __( 'After you import this demo, you will have to setup the slider separately.', 'your-textdomain' ),
),
);
}
add_filter( 'pt-ocdi/import_files', 'ocdi_import_files' );
Let me know, if you meant something else…
Take care!