Resampling method for downscaling photos

[djdelarosa25]

I downloaded this wallpaper from DeviantArt for my laptop but unfortunately, it was only available from 1080p up to 4K (my laptop display's resolution is only 1366x768).

For some reason, when setting the 4K photo as my wallpaper, lines would appear more jagged than the 1080p one, despite it being higher res. Could someone please explain that to me?

Because of that, I made a guess that by downscaling the original photo 768p, it would appear the sharpest on my screen. Would that be the likely outcome? Also, what resampling method should I use? And, should I use the lowest resolution (1080p) or the highest one (4K) as the base image for resizing?

Btw, I have disabled Windows 10's compression of wallpapers in the registry.

 

[Eggy]

This resembles the situation as with 4K TV sets.
Most providers only use 1080i or in some cases 1080P. (bandwidth issues)
Looking at 4K TV when using a HD (1080) image or film is often making the image more pixelated because the system has to distribute the 1080 pixels over 3840 px! (If the system has 'upscaling' software this is reduced)

I would take the 4K image and open it.
Start with 'image/resize' and change the resolution to 300px



then change the desired size and make sure the width and height are linked

 

[djdelarosa25]

What resampling method should I use?

 

[Eggy]

I'm not sure I understand what you mean...
I described it in my post...

 

[djdelarosa25]

I'm not sure I understand what you mean...
I described it in my post...

Like, Bicubic, Bicubic Sharpen, Bilinear, etc.

 

[Eggy]

Oops, forgot that one; use Bicubic Sharper (reduction)