The call to theme.init() accepts a range of different options, described below:

Key Usage Default value
credentials appId, apiKey and indexName credentials to query Algolia {}
hitName Name of the items to search, used in the XXX items found item
onSearch Method to call on each search. Called with query and helper. () => {}
placeholder Text displayed in the searchbar when query is empty Search for anything
searchParameters Optional searchParameters to pass {}
sidebar Array of additional InstantSearch widgets to add in the Sidebar []
transforms Transforms to apply to each hit {}

Also have a look at the Algolia frontend helper to lazyload your search result images.