I am not able to find a proper way to read an image from a URL and upload it using JavaScript/Ajax.
Suppose there is a URL: https://pbs.twimg.com/profile_images/15
https://pbs.twimg.com/profile_images/15
@DheerajAgrawal
see this example: http://jsfiddle.net/WQXXT/3004/
you should customize that, where it says:
alert('start upload script here');