Getting image urls of an instagram post

ig.js

len = (document.querySelector('._6CZji .coreSpriteRightChevron')) ? document.querySelectorAll('div.tN4sQ li._-1_m6').length : 1
index = 1
timer = setInterval(doing,500)
urls = []
function doing() {
    imgs = document.querySelectorAll('._97aPb img')
    if (index == 1){
        urls.push(imgs[0].getAttribute('src'))
    } else {
        urls.push(imgs[1].getAttribute('src'))
    }
    btn = document.querySelector('._6CZji .coreSpriteRightChevron')
    if (btn) {
       btn.click()
    }
    if(index == len) {
        clearInterval(timer)
    } else {
        index++
    }
}