Cannot import PNG or PSD Files D:

So basically I wanted to start using unity and im following the tutorial of Brackets how to make a 2D platformer game. In ep.2 (around 4mins) he drags 2 PSD files into Unity, when I go to do that it just comes up with a cross. Would anyone be able to help me so I can drag in PSD/PNG files in my Unity project. D:

Link to Tutorial Video:

Dont worry fixed it