Can Ты change the spot banner and Иконка without being the spot creator? And if yes, how?

link

No, Ты can't.
If Ты think either или both the Иконка and banner needs a revamp, Ты should try and find out who created the spot. What I usually do is post a pick asking this.
If that fails, then Ты can email papa and request the change. He can do it for you.
Hope this helps.