Are 4k Screenshots Possible with a 1080p Monitor?

[Mxyl V]

So, I noticed that screenshots in Dolphin (as far as I can tell) are always the size of the game window.  I'd like to take screenshots above 1080p, but the window size won't expand that far, probably since my monitor is 1080p (I've tried both selecting "Auto adjust window size" while increasing the internal resolution, and manually dragging it at the edge).  Would it be possible to take screenshots higher than my monitor's resolution?  
Thanks in advance!  

[KHg8m3r]

Technically yes

[Kurausukun]

To elaborate: Software exists that will let you raise your screen or games to resolutions above your monitor's resolution, but because your screen doesn't have enough pixels to display them (obviously), you will only see part of the image while the rest of it is offscreen. However, if you run Dolphin and take a screenshot under these circumstances, the full picture will come out at the intended resolution.