requests to fetch the same image

["?=Miron Kunz=?koi8-r?Q?"]

Hi 

in loader.cpp requestImage() will spawn a new job to fetch an image without checking if this
URL is already scheduled to be loaded though it's status is still Unknown.
It could be wastefull for images that are used to format document tables: many <img src=""> with the same URL but different width/height.

PS
in release 3.2

BR.