How can I quickly and easily downgrade the resolution of a photo?

[Zachary Boddy]

Photo Resolution

Hey guys, is there anyway to quickly and easily downgrade the resolution of a photo? I have some wallpapers that I'd like to use but they're too high resolution for my screen. As all of you know if you try to use too high resolution of a picture it's far too blurry to be usable.
My screen is 1368x766. I can use 1080 pictures--it's not perfect but it's not horribly blurry like higher resolution pictures are.
I'm not good with editing photos and such so I'd appreciate help.

 

[EL620]

You can try 'Fill' in background settings or resize the photo using ms paint. I don't have such problems but windows should automatically scale. Right click on the image and choose edit.