Hi,
The plugin will search the entire HikaShop database. If you don't see all the products possible as results, it's probably due to your configuration, but we would need more information on the issue to be able to say anything more precise.
Regarding the product image, the Joomla search results page doesn't handle images by default.
There are three solutions to have images on the results page:
1. You use that extension:
www.modulout.com/22-adsearch-for-hikashop.html
2. You customize the Joomla results page code( note that the link information is outdated):
www.akashchakrawarti.com/images-in-search-results-joomla/
3. Instead of using the Joomla search system, you use the HikaShop filters system:
www.hikashop.com/support/support/documen...-filter-listing.html
It will only search for HikaShop products (no Joomla articles, etc), but it will display the results as a HikaShop products listing and thus it will have all the display options of HikaShop products listings.