Hi @fuba182,
With regards to the WooCommerce REST API access codes that can be set from inside your WooCommerce site by following this documentation.
https://docs.woocommerce.com/document/woocommerce-rest-api/
For the developer level documentation, you can find located on this site below and this covers authentication and all of the endpoints and parameters which can be accessed via the REST API.
https://woocommerce.github.io/woocommerce-rest-api-docs/#introduction
For editing product data like images, you’ll want to look at the API Endpoint of products
for that.
https://woocommerce.github.io/woocommerce-rest-api-docs/#products
With regards to testing API calls, we have some information on testing API calls using an App called Postman and I’ve referenced that for you below too.
https://github.com/woocommerce/woocommerce/wiki/Getting-started-with-the-REST-API