Photoshop keeps blurring any pixel art i drag into it.

I'm working on a pixel art style project that required the files to be psd. I made the art through another program but have them saved as pngs. everytime i try to open them in photoshop to create a layered psd with all the files they become blurry. I have no idea how to fix this problem. 

I'm not scaling up the images. I'm just dragging the file in, it shows them unblured for a moment as intended then suddenly they are blurry. 

How do i fix this.