Where are my files? There's supposed to be on the desk top

Problem: I open up preview and I can't see the files I just put onto my desktop. The files should be right there, but they aren't.

Solution: There might be two reason why you can't see them.

1. You're sorting by date and you're expecting to see the file on top because you just created it. But the file might have no date, in which case it'll be toward the bottom. See below.

2. You have to click the button below so you can see all the files.