photoswipe initialize to set image size on load image

my-photoswipe-init.js

function MyPhotoswipeInit(pswpElement, PhotoSwipeUI_Default, items, options){
	var pswp = new PhotoSwipe(pswpElement, PhotoSwipeUI_Default, items, options);

	pswp.listen('imageLoadComplete', function(index, item) { 
		if ( item._myLoaded ) {
			return;
		}
		var img = document.createElement('img');
		img.onload = function(){
			item.w = this.naturalWidth;
			item.h = this.naturalHeight;
			item._myLoaded = true;
			pswp.updateSize(true);
		};
		img.src = item.src;
	});

	pswp.init();

	return pswp;
}