why does pixel not do whole image when I choose one of my pics as a wallpaper?

[mistyisland]

When I try to use a picture as wallpaper I only get about 25% of it. the galaxy s6 never did that. 25% of a picture doesn't even make sense.

 

[DJM626]

I get full images when I select one of the pics I took with mine. Maybe it has something to do with how the pic was taken?

 

[Ry]

What's the resolution of the picture?