It seems that image links generated only when you click on each small image.
Please try this one out:
{"_id":"heatsets2","startUrl":["https://www.amazon.com/s/ref=sr_nr_p_36_2?fst=p90x%3A1%2Cas%3Aoff&rh=n%3A172282%2Cn%3A541966%2Ck%3Aheadset+with+microphone%2Cp_85%3A2470955011%2Cp_n_condition-type%3A2224371011%2Cp_36%3A1253505011&keywords=headset+with+microphone&ie=UTF8&qid=1530413105&rnid=386442011"],"selectors":[{"id":"LINKS","type":"SelectorLink","selector":"div.a-row.a-spacing-small a.a-link-normal","parentSelectors":["_root"],"multiple":true,"delay":"2000"},{"id":"TITLE","type":"SelectorText","selector":"h1.a-size-large span.a-size-large","parentSelectors":["LINKS"],"multiple":false,"regex":"","delay":0},{"id":"PRICE","type":"SelectorText","selector":"td.a-span12 span.a-size-medium","parentSelectors":["LINKS"],"multiple":false,"regex":"","delay":0},{"id":"IMAGE 1","type":"SelectorImage","selector":"img","parentSelectors":["showall_"],"multiple":false,"delay":0},{"id":"showall_","type":"SelectorElementClick","selector":"li.image div.imgTagWrapper","parentSelectors":["LINKS"],"multiple":true,"delay":"","clickElementSelector":"li.a-spacing-small","clickType":"clickMore","discardInitialElements":false,"clickElementUniquenessType":"uniqueCSSSelector"}]}
It will go through each link, scrape text and price, then click each small image to have all bigger ones scraped.