Since that is an artist rendering and it was done in May 2017, I doubt it has anything to do with Assange. I don’t know if the artist used a photo of the White House, or created the entire image himself.
Something is in that window, but I cannot sharpen the image well enough to make it out.
Our guys could have photo shopped it for us. By the time I get back from work I hope the Anons and the Freeq’s will ha e figured it out for me. Happy Hunting!
I think it's just an artifact of the red paint splash that was an overlay on the WH. They tried to color match it out and did a shoddy job. If you notice, the pattern lines up with the rest of the red brick pattern on either side.