jQuery Pjax
pushState + ajax = pjax
Layzr.js
A small, fast, modern, and dependency-free library for lazy loading.
Query Loader2
Version of the QueryLoader by Gaya Design. Preload images with ease.
Nanobar
Very lightweight progress bars. No jQuery
Lazyload
Tiny, dependency-free async JavaScript and CSS loader.
Java Script Load Image
JavaScript Load Image is a library to load images provided as File or Blob objects or via URL. It returns an optionally scaled and/or cropped HTML img or canvas element. It also provides a method to parse image meta data to extract Exif tags and thumbnails and to restore the complete image header after resizing.