Calculation for blacksquaring an image. I have a friend working on a Windows app. Not easy to do on a phone apparently, but he asks

i wonder if a black border would work?

that would allow more of the image to be shown as it would be spread across the edges

Calculation:

911 x 907 = 826277 sq/px

20% = 165256

4 corners = 41314

sqr root = 204 x 204 pixels

Hope this helps