scroll downvi phrasalphrasal verb, intransitive: Verb with adverb(s) or preposition(s), having special meaning and not taking direct object--for example, "make up" [=reconcile]: "After they fought, they made up."
(move cursor down the screen) (电脑屏幕光标)
向下移动，向下滚动
You can use the wheel on the mouse to scroll up and down the screen. The reason you can't see the image at the bottom of the document is because you haven't scrolled down enough.