How do I resize opening image to display entire height?

I am talking about the image that first appears before you log in. I have Photoshop, yet it seems whatever I do it crops the height. I am not concerned with the width but what the entire height. My resolution is 1920x1280.

Also, my screen saver consists of images, of which some of them are being cropped as well. What is the max width & height in pixels I need so I get no cropping>

Thanks!

Is 1920x1280 your native resolution for your monitor? Meaning, is that what it's official rating is?
If so, then that should be the resolution, why it is cropping, I would not know, that doesn't make much sense.

However, I have an image that I am using for my lock screen that is 1920x1080, but my native resolution is 1600x900
I do not get any cropping.

On the screen saver, if you are using the Photos screen saver, it should resize them to fit the screen

You may need to reinstall or update your video drivers.

Also, have you done any tweaking to your system? Made any changes at all? Reg Keys, customizations?