My Server header image is showing white BG with red questions mark.
I made an image size of 512 px x 256 px then uploaded to img hosting site.
This is my original image file
and this is the error 
Server Header Image
How do i fix it?

Thank you

You are trying to use a webpage as an image: https://imgur.com/vWcq8tb

You need to use a direct image URL: https://i.imgur.com/vWcq8tb.png