This is a sample on how to search the fields of a smart form using the Search Manager API for testing purposes. This was tested on 9.1 SP1 using SOLR Search.
*Note: In order to search the fields of a smart form the fields have to be indexed
Where to find you XPath information under Settings > Configuration > Smart Form Configuration:
*Note: If you want to search for numeric fields use:
If you want to return an image instead of just the path use the /img/@src xpath and on the front end and display it with an image control: