2d sprites different resolution in Unity / Explorer

I'm building a UI-Based game and created some spritesheets. After importing these spritesheets to Unity, I saw in the lower right corner that the resolution of each sprite is different to the actual resolution I created the spritesheet in (windows shows the higher resolution as well).

The resolution I created this sprite in, is 320*320 per sprite (my sheet has 10 sprites, so it's 3200x320). In Unity this sprite is shown as 205*205 / 2048*205.

I set Sprite Mode to Multiple, Filter Mode to Point(no Filter) and Compression to none. Then I sliced the sheet.

Can someone explain why the resolution is different to the actual .png?