You can upload images to the WP Media Library as well and add the image description to the image. WPFTS Pro can search these images by the description then.
Alternatively, you can create a special post type and upload images as "Featured Image" to each of these posts, and put the description and special information to the post_content or additional meta field(s) - depending on the number of data fields and type of information.
In both cases, WPFTS Pro will help you with the search.
It looks like this message is generated by some other plugin or maybe "auto-suggestion" feature of the theme. Could you try to check if there is an option in the theme settings or some AJAX Search plugin? Could you try to disable it?