how to make landscapes full screen

[katya1049]

when i click full screen option the picture is not full screen. some do not fill the entire window. for example, on windows 10 i use a screen resolution of 3840 x 2160 and the some of the landscapes i installed are widescreen with the black bars on each side. but the animated "valley" is stretched perfectly with no black bars. how make the picture appear more like "valley" and less widescreen

[katya1049]

I was able to change the resolution of the picture with the help of an online resize program. I only had to change the pixel dimensions though. It took a while to make the adjustments because each picture was a different size with the black bars on the sides not always the same width when its applied as a landscape.