A lot of web-based image resizing tools require you to upload the images in order to resize them. But Resizer.co is different. It helps you resize your images dynamically through a URL.
http://www.makeuseof.com/dir/resizerco-dynamic-image-resizing/
DawsonITE is a blog devoted to Educational Technology. It's compiled by Rafael Scapin, Coordinator of Educational Technology at Dawson College in Montreal (Canada).