.evaluate() is not returning all dom elements

[pragun16]

I'm trying to find all the img tags within a dom using the following code:

imgSrcs = await chromeless
        .goto(url)
        .evaluate(() => 
            [].map.call(document.querySelectorAll('img'), img => img.src)
        );

so if I do something like imgSrcs.length in the js file, I get less img tag count than that from the browser console. what could be the possible reason?