http:// can remove this? Almost all img link already come with http, need to delete then anly can paste..

I kinda agree with this,
though some people might be new to this so it doesn't hurt me really

What's the problem?

The "http://" is to give the clueless an idea that the system is asking for a HTTP URL.

To add another point
Currently, the "http://" is highlighted automatically, so users can just paste into the box without worrying about having to delete the "http://".