Even sideways, this picture is adorable!

@Deon Miller  
Because you used your phone in portrait mode.  
The picture is always taken in landscape mode - that’s what the camera sensor does - but there’s a bit of information in the JPG file that tells that the picture should be shown in portrait mode. In short, the image is not actually rotated, because it would be cumbersome for the phone to do it, but it’s shown vertically.
 
But when you upload it to Derpibooru, the file gets mangled to save space and that information is lost. So the picture is shown in the original landscape mode.
 
Solution: rotate the image in your PC before uploading it to Derpibooru.  
There are simple and free programs that can do it without losing quality, like Irfanview (and the JPEG plugins).

@BigMax  
This. Why is it that every damn time I post a picture with my phone straight, why does it turn the other direction?

@Deon Miller  
About what?

Guys, I need help.

WHAT THE FUCK?!!!