你 can't.
In most quizzes, the Prizes 图片 are the same, because they are generated 由 Fanpop.
See the default prize 列表
link But, on some 测验 like the Twilight 或者 the Harry Potter quiz, the prizes 图片 are different because the F4 made those custom prize sets.
But, if 你 want to know 更多 about this see
link 文章 (there may be something in there about changing the 测试 prizes 图片 ;D).
