duckduckgo_image_url_grabber.js

// grab the URLs
var urls = $('.tile--img__img').map(function(idx, el) { return el.src});

// write the URls to file (one per line)
var textToSave = urls.toArray().join('\n');
var hiddenElement = document.createElement('a');
hiddenElement.href = 'data:attachment/text,' + encodeURI(textToSave);
hiddenElement.target = '_blank';
hiddenElement.download = 'urls.txt';
hiddenElement.click();