So far I've been able to filter the call to only obtain products within a section with this url:
The problem is Etsy api doesn't accept Images association for ShopSection: https://www.etsy.com/developers/documentation/reference/shopsection#section_associations
So how can I list products with thumbnails within a section?
Bonus Question: Etsy always returns null for item_height and item_width even if the product actually has a height and a width, is this a bug?
Found the solution, turns out you can just add a second level of listing for the images in the url: https://openapi.etsy.com/v2/shops/FOO-USER/sections/21162893.js?callback=JSONP_CALLBACK&api_key=BAR-KEY&includes=Listings(price,title,shop_section_id,description,state,item_width,item_height)/Images(url_570xN)&fields=title