function makeLightboxes(photoset) {
	// get image containers in photoset
	let image_containers = photoset.getElementsByClassName("image-container");

	// loop over image containers
	for (let i = 0, n = image_containers.length; i < n; i++) {
		// add click event to image container
		image_containers[i].addEventListener("click", function() {
			// current is the image's index in the photoset
			// due to tumblr reasons, it starts at 1
			let current = i + 1;

			// activate lightbox
			lightbox(image_containers, current);
		});
	}
}

function lightbox(image_containers, current) {
	// array of lightboxes for each image in photoset
	// lightbox is represented by an object
	let lightboxes = [];

	// loop over image containers
	for (let i = 0, n = image_containers.length; i < n; i++) {
		// create object for image container
		let image_container = image_containers[i]
		let arrayContents = {
			"width" : image_container.dataset.width,
			"height" : image_container.dataset.height,
			"low_res" : image_container.dataset.lowres,
			"high_res" : image_container.dataset.highres,
		}

		// add object to array
		lightboxes.push(arrayContents);
	}

	// activate built-in tumblr function
	Tumblr.Lightbox.init(lightboxes, current);
}

function makePhotoset(photoset) {
	// get image containers in photoset
	let images = photoset.getElementsByClassName("image-container");

	// get layout of photoset -- formatted as string of numbers of images per row
	// e.g "231" means row of 2 images, row of 3 images, row of 1 image
	let layout = photoset.dataset.layout;

	// loop over each row
	for (let i = 0, n = layout.length; i < n; i++) {
		// get number of images in row
		let cols = layout.charAt(i);

		// create row
		// row is a div with classes "photo-row" and "photo-row-n"
		let row = document.createElement("div");
		row.classList.add("photo-row-" + cols);
		row.classList.add("photo-row");

		// loop over number of images in row
		// move the right amount of images to row
		for (let j = 0; j < cols; j++) {
			row.appendChild(images[0]);
		}

		// add row to the photoset
		photoset.appendChild(row);
	}
}